Become a trivia master with a multiple-choice quiz for elementary schoolers! A fun problem collection that captivates both kids and adults

3 yen

The 1-yen coin is made of aluminum. The raw material cost per coin is about 0.3 yen, but when you add processing and other expenses, it comes to 3 yen. By the way, it reportedly costs 10 yen to make a 5-yen coin, 13 yen for a 10-yen coin, and finally drops to 12 yen for a 50-yen coin, so try remembering these together.

Because the light is reflecting and it's hard to see.

There is a theory that, in postwar schools, the baby boom led to an increase in the number of students, and in the packed classrooms, the glare on the blackboard from the windows made it hard to see from the front row, which is why the boards were changed to green. Nowadays, more schools are using whiteboards and monitors for lessons, but many people still associate school classrooms with blackboards.

so as not to wipe my nose

The origin of suit sleeve buttons is said to trace back to Napoleon, renowned as a French hero. During France’s invasion of Russia, it’s said that soldiers, suffering from the extreme cold, wiped their runny noses on their jacket sleeves. As a result, when they marched, many soldiers’ sleeves were stiff with dried mucus. A leading theory holds that metal buttons were added to the sleeves to prevent soldiers from wiping their noses on them.

20 hours

Eucalyptus, the main food of koalas, is fibrous, highly toxic, and low in nutrients, so digesting it requires a lot of energy. For this reason, it’s said that they sleep about 20 hours a day to conserve energy. On the other hand, when they really run, they are said to reach about 30 km/h, which shows just how fascinating animals can be.

The way the fabric moves

People tend to think bulls go wild because of the color red, but in reality, bulls see in monochrome and cannot distinguish colors. To protect themselves from predators, they react to unfamiliar or moving objects; due to this instinct, they charge at a fluttering cloth. Therefore, the color of the cloth is irrelevant. In bullfighting, however, red is used to evoke images of blood and danger, which serves to excite the audience rather than the bull.

hair

Byakugō refers to the long, white, right-twisting hair that grows slightly above the space between the Great Buddha’s eyebrows. It is said that the light emitted from the byakugō illuminates the world, and if extended, it is about 4.5 meters long. In Hinduism, some deities are depicted with a third eye in the same position, so it can be easy to confuse the two.

8 pieces

Because of how they look, people often assume octopuses have eight legs and squids have ten, but in fact squids also have eight legs. The two that make them appear to have ten are called tentacular arms, used for catching prey, and are counted as arms rather than legs. If you look closely, you’ll notice they differ in shape and length from the other eight, so be sure to observe them carefully.