The reason why four tens are equal to one hundred is:10 *10+10/0 =100.

Ten times ten is one hundred, then add ten and subtract ten, that is, there is no addition or subtraction, and the result is one hundred.

If multiplied, it is 10000.

According to the corresponding multiplication law, two 10 times three digits, two 10 are reduced to zero, and one hundred plus zero is still one hundred.