1. If the length of "one foot" is 8 cm and the length of the desk is 7 feet, then the length of the desk is 56 cm. If each step is 65 cm, then when you go to school, you can count how many steps you have taken and calculate how far it is from home to school.

2. Height is also a ruler. If the height is 150 cm, hold a big tree and put your hands together. The length of this tree is about 150 cm. Because everyone's arms are flat, the length and height between the fingertips of both hands are similar.

3. If you want to measure the height of the tree, shadows are also helpful. Just measure the length of the shadow of the tree and your own shadow. Because the height of the tree = shadow length × height ÷ graph length.

If you want to know how far the mountain ahead is from you, you can ask the sound to help you measure it. Sound can travel 33 1 meter per second, so you can hear the echo by shouting at the mountain and watching it for a few seconds. Multiply the time to hear the echo by 33 1 and divide it by 2.

5、? "Astronomical Recorder" Coral scientists found that corals record time on themselves: they "carve" an annual ring pattern on the body wall every day and "carve" 365 annual rings a year, no more or less.

So, if you want to know their age, just count the annual rings on their body walls. Scientists also found that 350 million years ago, corals "carved" 400 rings instead of 365. The reason is that the earth's rotation was only 2 1.9 hours a day, not 365 days a year, but 400 days.

A short story of a mathematical scientist

Gauss was interested in mathematics when he was in elementary school. One day, Mr. Baxter, the math teacher, was a little unhappy. As soon as he entered the classroom, he said to his classmates with a straight face, "Today's class is calculated by yourself. Whoever finishes the calculation first will go home for dinner first. " With that, he wrote such a topic on the blackboard:

1+2+3+……+ 100=?

The students immediately took out their exercise books and bowed their heads and calculated carefully. Burt sat reading a novel. Who knows, he just finished reading a page when little Gauss raised his hand and reported to the teacher:

"Teacher, I have finished this problem."

"finished?" Bert waved angrily. "You must be so quick. Do it again! "

"Can't be wrong. I checked and checked. " Gauss said confidently. "Bert went to Gauss's seat and picked up his exercise book. The answer is "5050", which is obviously true.

"How do you calculate?" Bert asked in some surprise.

Gauss answered matter-of-factly: "I found that the sum of the two numbers in this question is 10 1, and the total is * * * 5010/,so the answer should be: 50×1= 5050."

"Great!" Baxter patted the table excitedly, and then loudly said to all the students, "I didn't expect that there would be a math prodigy among you!" " "

Since then, Mr Burt has completely changed his views on rural children, especially Gauss. Later, under the careful training of Mr. Bertrand, Gauss became more and more interested in mathematics and gained more and more accomplishments. /kloc-at the age of 0/7, he discovered the quadratic reciprocity law in number theory.