/kloc-how big is the record of mathematical practice activities of 0/100 million people as follows:

This afternoon, I measured how big is 100 million? I took ten or more coins first, so I took out a starting amount.

So I quickly took out a ruler and a coin.

The first time I thought it was inaccurate, the second time I came again. The teacher said that to measure something, it must be more than three times, otherwise it may not be accurate. So I measured it again and got an answer of about one centimeter, so I thought 1 billion was equal to 10000000000 square decimeter.

Then I calculated that 100 coins are about one centimeter, and finally I used the division formula:

1000000000 ÷100 =100000000 will know the final answer.

The answer is 10000000 sets 100 block is about 1 billion.

This observation made me know that we should observe things three or more times.

The meaning of ratio and proportion:

The meaning of ratio is the division of two numbers, which is also called the ratio of two numbers, while the meaning of ratio is that the formula that indicates that two ratios are equal is called ratio. The ratio is the division of two numbers, and there are two items; Proportion is an equation, which means that two proportions are equal and there are four terms. So the meanings of ratio and proportion are different. Moreover, the comparison symbol does not have the meaning of brackets, while in another form, the score has the meaning of brackets!