Estimation Questions with Answers: The Big Collection

Answer: 7

A giraffe's neck has only 7 bones. That is the same number as in a human neck. But each single bone is up to 25 centimeters long. Thanks to these long neck bones, the giraffe's head can reach the highest leaves.

Answer: 0

A shark has zero bones in its body. Its whole skeleton is made of cartilage, the same stuff as in our ears. This keeps the shark light and flexible in the water. Only its teeth contain hard, bone-like material.

Answer: 38 minutes (Anglo-Zanzibar War)

The shortest war in history lasted just 38 minutes. It was the Anglo-Zanzibar War in the year 1896. Britain fought against the new Sultan of Zanzibar. The British fleet shelled the palace into rubble. After that the war was already over.

Answer: The Antarctic Desert

Antarctica is the largest desert in the world. It covers about 14 million square kilometers. Despite all the ice and cold it officially counts as a desert. The reason is very low precipitation. In some places it has barely rained or snowed for millions of years.

Answer: About 21,196

The Great Wall of China is about 21,196 kilometers long. That equals roughly half the distance around the Earth. It was built over more than 2,000 years, piece by piece. Despite the myth, you cannot see it from space with the naked eye.

Answer: Canada

Canada has the longest coastline in the world. It measures about 202,000 kilometers. The reason is the many islands in the north of the country. If you walked along the whole coast, it would take you more than 20 years.

Answer: 5

An earthworm has five heart-like organs called aortic arches. They pump blood through its long body. The worm is a real hero for the soil in our gardens. It loosens the earth and helps plants to grow strong roots.

Answer: 270

A baby is born with around 270 bones. An adult has just 206 left. Many small bones fuse together as we grow up. This happens especially in the skull and the spine, where bones merge into bigger units.

Answer: 100,000

A human heart beats about 100,000 times per day. That is around 70 beats per minute. Over a full life, this adds up to more than 2.5 billion beats. Each day, it pumps around 7,000 liters of blood through the body.

Answer: About 2.5

There are about 2.5 million ants for every human on Earth. In total that is around 20 quadrillion ants. Their combined weight equals the weight of all humans together. This makes ants one of the most successful creatures ever.

Answer: About 60 percent

A human and a banana share about 60 percent of their DNA. That sounds crazy, but it comes from very old, shared cell building blocks. Almost all life on Earth uses the same basic parts. Still, a human is of course very different from a banana.

Answer: Canada

Canada has the most lakes of any country in the world. Over 2 million lakes lie within its borders. Together they make up about 9 percent of the country's land area. No other country comes even close to this number.

Answer: Up to 72

A snail can sleep up to 72 hours in one go. In dry times it can even sleep for up to three years. It pulls into its shell and seals the entrance. This way it survives long periods without water or food.

Answer: Up to 9

A cockroach can live up to nine days without its head. It breathes through small holes on the body, not the mouth. Only when it runs out of water does it die. The nervous system keeps working without a brain.

Answer: Wombat

The wombat is the only animal that produces cube-shaped droppings. Its intestines press the poop into the blocky form. The cubes do not roll away and mark the territory. Australian scientists even got an Ig Nobel Prize for this.

Answer: Turtle

Some turtles really do breathe through their bottom. They take in oxygen through a rear opening called the cloaca. This helps them survive under ice in winter. They can stay underwater for months this way.

Answer: Garden snail

A garden snail has up to 25,000 tiny teeth. They sit on a rasping tongue called a radula. With it the snail scrapes off leaves and plants. The teeth get replaced regularly as they wear down. Sometimes you can even hear the rasping on a lettuce leaf.

Answer: Emus (Great Emu War 1932)

In 1932 Australia fought a real war against emus. The birds were destroying too many fields. The army came in with machine guns but could barely hit the fast animals. After a few days the soldiers gave up. The emus had won.

Answer: War of the Scilly Isles against the Netherlands

From 1651 to 1986 the small Scilly Isles in England were officially at war with the Netherlands. It is just that nobody had noticed. Nobody fought, nobody died. Only in 1986 did both sides sign a peace treaty. This ended the longest peaceful war in history.

Answer: The War of Jenkins' Ear (1739)

In 1739 a real war started between England and Spain because of an ear. A Spanish officer had cut off the ear of English captain Robert Jenkins. Jenkins later showed the ear in parliament. After that England declared war on Spain. The war lasted nine years.

Answer: A pizza

The first known online order was a pizza from Pizza Hut back in 1994. A student sent it from his computer straight to the local branch. Today millions of people order food online every day. So a small start left very big footprints.

Answer: The Chinese

Toilet paper is not a modern invention. As early as the 6th century the Chinese used paper for the toilet. In the 14th century it was even perfumed for the imperial family. In Europe people used leaves, straw or rags for much longer. Only in 1857 did the first toilet paper appear in the USA.

Answer: 30

A sloth takes about 30 seconds to cover a single meter. On the ground, it is even slower than up in the trees. Its body uses almost no energy. That is why it mostly eats leaves and sleeps up to 20 hours a day.

Answer: Kangaroo

A kangaroo cannot walk backwards. Its big hind legs and thick tail block reverse movement. That is why Australia puts the kangaroo on its coat of arms. The country should only move forward, like the animal.

Answer: 8

A spider has eight legs. That is why it belongs to the arachnids and not to the insects. Insects always have only six legs. At the tips of its legs are fine hairs. With those, the spider feels every little movement in its web.

Answer: 2

A Bactrian camel has 2 humps on its back. The humps store fat, not water, as many people think. The dromedary, in contrast, has only one hump. Bactrian camels live in the cold deserts of Central Asia.

Answer: 4

A cow has 4 stomachs. Each stomach has its own job in digesting grass. The cow brings up the food again and chews it a second time. This is called chewing the cud, and it helps break down the plant fibers.

Answer: 42

An adult dog has 42 teeth in its mouth. Puppies start with only 28 milk teeth. The strong canine teeth are used to grab prey. The molars in the back can even crush bones. A human, in comparison, has only 32 teeth.

Answer: 7

Earth has seven continents. They are Africa, Antarctica, Asia, Australia, Europe, North America and South America. Asia is the largest and Australia the smallest. In some countries people count only six, joining Europe and Asia together as Eurasia.

Answer: Pacific Ocean

The Pacific Ocean is the largest ocean in the world. It covers about 165 million square kilometers. That is more than all the land on Earth put together. Deep inside it lies the Mariana Trench, the deepest point on the planet.

Answer: 6

A butterfly has six legs. Like every insect, it has three pairs of legs. Really cool is its long tongue. It looks like a drinking straw that rolls up. The butterfly uses it to sip sweet nectar from deep inside flowers.

Answer: 7

A typical seven-spot ladybug has 7 spots on its wings. But there are also species with 2, 10, or 22 spots. The spots warn predators about the bitter taste. Ladybugs are seen as lucky charms in many countries.

Answer: 20

Koalas sleep up to 20 hours a day. Their main food is eucalyptus leaves, which give very little energy. That is why they rest so much to save their strength. The leaves are toxic to most animals, but koalas can digest them.

Answer: 71

About 71 percent of Earth's surface is water. Most of it is seas and oceans, only a tiny part is freshwater. That is why our planet looks so blue from space. No wonder it is often called the blue planet.

Answer: 85

The place name has 85 letters and lies in New Zealand. It names a hill on the North Island of the country. In the Maori language the name tells a short story about a man. Guinness World Records lists it as the longest official place name on Earth.

Answer: 44

There are 44 landlocked countries in the world. Most of them lie in Africa, Europe and Asia. Uzbekistan and Liechtenstein are even double landlocked. That means all of their neighbors are landlocked too, with no sea access at all.

Answer: 10,984

The Mariana Trench reaches about 10,984 meters down. If you dropped Mount Everest into it, more than two kilometers of water would still cover the peak. Only a handful of people have ever been down there. It is the darkest spot on our planet.

Answer: 71,000

An Arctic tern flies about 71,000 kilometers every year. That is the longest migration of any animal on Earth. It travels from the Arctic to the Antarctic and back each year. Over its lifetime, it covers more distance than three trips to the moon.

Answer: ~400

A Greenland shark can live for about 400 years. That makes it the oldest vertebrate in the world. It lives deep in the icy northern seas. Its movements are extremely slow. A female only has her first offspring at around 150 years old.

Answer: 38 trillion

About 38 trillion bacteria live inside the human gut. That is even slightly more than the body has its own cells. Most of them are very helpful and support digestion. Without them we would not feel very well.

Answer: 86 billion

The human brain holds about 86 billion nerve cells. Each one can talk to thousands of others. Together they make thinking, dreaming and feeling possible. The whole brain weighs only around one and a half kilograms.

Answer: About 60,000

Every day about 60,000 kilograms of cosmic dust fall onto Earth. Most of it is so tiny that you cannot even see it. A small part ends up in our hair and on the sofa. So a tiny bit of the dust in your home really comes from space.

Answer: About 500,000 kilograms

A normal white cloud in the sky weighs around 500 tons, which is half a million kilograms. That is as heavy as 100 fully grown elephants. Still it floats in the sky because the tiny water droplets are carried by warm air. Nature is sometimes really astonishing.

Answer: 116 years

The Hundred Years' War actually lasted 116 years, from 1337 to 1453. It was fought between England and France. It was about the French crown and land. In the end France won and England lost almost all its mainland territory. Joan of Arc became a hero during the war.

Answer: 267

According to the Vatican's official papal list, there have been 267 popes so far. The first was the Apostle Peter (around 30 to 64 AD). The current pope is Leo XIV. He was elected on May 8, 2025, after the death of Pope Francis. The exact count is debated. Some historians include so-called antipopes, others don't.

Answer: About 99,000

Google answers around 99,000 searches every second. That adds up to over 8 billion queries each day. Huge data centers all over the world handle it in the background. Hardly anyone thinks about that when they quickly look something up.

Answer: 11

Answer: 54

Africa has 54 recognized countries. That makes it the continent with the most nations. The countries are very different, from tiny island states to huge desert nations. Together they are home to more than 1.4 billion people.

Answer: 1

China uses just one single time zone across the entire country. Geographically it would be wide enough for five. But the government chose Beijing time for everyone. In the west the sun only rises around noon. This still leads to quirky everyday situations.

Answer: Sweden

Sweden has the most islands of any country in the world. There are more than 267,000 islands and skerries along its coasts. Only a small number of them are actually inhabited. Many Swedes own a little summer house on one of these islands.

Answer: Maldives

The Maldives is the flattest country in the world. Its highest point sits just 2.4 meters above sea level. The nation is made up of almost 1,200 small coral islands. Even a small rise in sea level threatens many of them. The government is looking for ways to fight climate change.

Answer: Istanbul

Istanbul sits on two continents, Europe and Asia. The two sides are divided by the Bosphorus strait. Three large bridges connect them. The city used to be called Constantinople and was capital of a huge empire. Today around 16 million people live there.

Answer: Lesotho

Lesotho sits completely inside South Africa with no other neighbors. It is one of the very few countries in the world surrounded by just one other state. The country lies high in the mountains and gets very cold in winter. A little rocky island right in the middle of Africa.

Answer: Nepal

Nepal's flag is made of two stacked triangles. It is the only national flag in the world that is not rectangular. The triangles stand for the sun and the moon. A real eye catcher among all the square flags.

Answer: Papua New Guinea

Papua New Guinea has more spoken languages than any other country. There are more than 800 different languages. Many of them are used only in small villages. The reason is the many mountains and valleys, which kept groups separated for a long time.

Answer: 1 (The Nile)

Egypt has only one real river, the Nile. It is the country's lifeline. Almost all cities and farms sit right along the Nile. Without it, Egypt would be pure desert. The ancient pharaohs also built their kingdoms on its banks.

Answer: 120

A cheetah reaches up to 120 kilometers per hour. That makes it the fastest land animal in the world. In just three seconds, it is as fast as a sports car. Yet it can only keep up the sprint for a short time. After that, it must rest in the shade for a long while.

Answer: 22

An elephant baby grows for 22 months inside its mother. That is almost two years, the longest pregnancy of any land animal. At birth, the calf already weighs around 100 kilograms. The mother cares for her child for many years.

Answer: 3

An octopus has three hearts. Two pump blood through the gills, the third sends it through the rest of the body. Its blood is blue because it uses copper instead of iron. When an octopus swims, the main heart stops, which tires it quickly.

Answer: 32

A leech has 32 brains inside its body. More precisely, they are 32 nerve ganglia working together. Each one controls a segment of the body. This lets the leech stretch in any direction. That is why every part of the body reacts instantly to touch.

Answer: 32

A cat has 32 muscles in each ear. For comparison, a human has only 6. That is why a cat can rotate its ears independently. This lets it hear sounds from every direction, even when it stays lazy on the couch.

Answer: 45

A giraffe's tongue is about 45 centimeters long. That is as long as a school notebook. Its color is dark blue to purple. This protects the tongue from sunburn. With it, the giraffe can even grab pointy leaves between thorns without getting hurt.

Answer: 300

An adult great white shark carries up to 300 teeth in its mouth. They sit in several rows, one behind the other. If it loses a tooth, a new one grows in right away. Over its lifetime, it uses up thousands of teeth.

Answer: Mosquito

Mosquitoes kill about 725,000 people every year. They spread diseases like malaria and dengue. Sharks only kill about ten people per year. This makes the mosquito the deadliest animal in the world. Only the female bites because she needs blood for her eggs.

Answer: Platypus

The platypus is a mammal that lays eggs. It lives in Australia and looks like a mix of duck and beaver. The males have venomous spurs on their hind feet. After hatching, the babies drink milk from the mother.

Answer: 270°

An owl can turn its head 270 degrees. That is three quarters of a full circle. Its eyes are fixed in the skull and can barely move. So the owl has to swivel its head that far around to look behind itself without moving its body.

Answer: 1,300,000

About 1.3 million Earths would fit inside the Sun. The Sun has a diameter of around 1.4 million kilometers. Still, it is only a medium sized star. Some stars out there are a thousand times bigger than our Sun.

Answer: Minus 270

The average temperature of space is about minus 270 degrees Celsius. That is only a few degrees above the absolute zero point. The leftover warmth is an echo from the Big Bang. Even the coldest winter night on Earth feels cozy warm by comparison.

Answer: About one trillion

The human nose can tell apart about one trillion different smells. For a long time people thought it was only around 10,000. A new study found out there are many more. That is why we so easily recognize grandma, summer rain and fresh bread.

Answer: About 8

A sunbeam needs about eight minutes and twenty seconds to reach Earth. Before that, it was stuck inside the Sun for around 100,000 years. If the Sun suddenly turned off, we would still have eight minutes of light. So the sunlight you see right now is already a bit old.

Answer: About 3 million

Around 3 million emails are sent globally every single second. That adds up to about 300 billion emails in a single day. Experts estimate that 45 percent of them are spam. The first ever spam email went out to 400 people back in 1978.

Answer: Over 100 million

A modern car runs on over 100 million lines of code. That is more than a fighter jet or Windows 10. Around 100 small computers control the engine, brakes, windows, and radio. A Tesla or BMW is really software on wheels today. That is why repairs often take longer than they used to.

Answer: About 790 grams

The Motorola DynaTAC 8000X from 1983 weighed nearly 800 grams. It stood about 25 centimeters tall and was fondly called the brick. Its battery lasted just 30 minutes of talk time. Still, it was the ultimate fancy status symbol back then.

Answer: 20,000

A great white shark can go through up to 20,000 teeth in its life. When one tooth falls out, a new one moves up right away. The teeth sit in several rows behind each other. This way the shark always has sharp tools for hunting.

Answer: 70 years

Queen Elizabeth II sat on the throne for a very long time. She reigned for 70 years, from 1952 to 2022. This makes her the longest reigning monarch in British history. During her time she saw 15 different prime ministers and huge changes in the world.

Answer: Over 1,000 (estimated)

Genghis Khan had many wives and partners, so his family grew enormous. Researchers believe around 16 million men in Asia today are his direct descendants. They can see this in a special pattern in the DNA. No other person has left behind so many known descendants.

Answer: 122 years

Jeanne Calment from France lived to be 122 years and 164 days old. She died in 1997. This makes her the official world record holder as the oldest person of all time. As a young girl she even met the painter Vincent van Gogh in her shop. She found him rude and dirty back then.

Answer: The Great Pyramid of Giza

The Great Pyramid of Giza was the tallest structure in the world for an unbelievably long time at 146 meters. It held the record for a full 3,800 years. Only in 1311 did Lincoln Cathedral in England overtake it. Its spire later collapsed, briefly making the pyramid the tallest again.

Answer: About 50,000

The Colosseum in Rome had room for around 50,000 people. That made it as big as a modern football stadium. Spectators watched fights between gladiators or animals. Entry was actually free, the emperor paid for it. There was even a huge tent roof to block the sun.

Answer: About 2 hours

Leonardo da Vinci supposedly had an unusual sleep schedule. Every four hours he took just a short nap of 20 minutes. In total he slept only about 2 hours per day. Today this method is called polyphasic sleep. Whether it was truly healthy nobody really knows.

Answer: About 300 million

Two thousand years ago only around 300 million people lived in the whole world. That is fewer than the population of the United States alone today. Today we are over 8 billion. The world population grew very slowly for a long time. Only in the last 200 years did it shoot up fast.

Answer: 13 days

The Cuban Missile Crisis lasted only 13 days in October 1962. The Soviet Union had placed nuclear missiles on Cuba. The USA spotted them from the air. Both countries were on the edge of nuclear war. In the end the Soviets pulled back their missiles and the world felt relief.