Answer:
4
Step-by-step explanation:
The square of 100 means that 100 is being multiplied by itself. So the square of 100 is 100x100 = 10,000
Whenever you multiply a number by a multiple of 10, you simply add the number of 0s onto the end of the original number, so 100 originally has 2 zeros, so multiplying by 100 will add on another 2 zeros.
So, the number 10,000 which is the square of 100 has 4 zeros.
Hope this helped!
