Answer:
100x100=10,000
A short and easy trick is to multiply only the first number since the rest are zero. So, multiply 1 and 1: 1 x 1. What do you get? 1, of course. Then, add the rest of the zero's after that. In 100, there are two zero's. In 100, there are two zero's. What is two plus two? Well: 2 + 2 = 4 so, four zero's. After that, add the 4 zero's after the 1. One is extremely important in this problem. 1, one zero, 10, two zero's, 100, three zero's, 1,000, and finally, four zero's, 10,000. So, the trick is to multiply the one by the other one, get 1, and add the zero's in the other numbers. This can work as long as it is something like: 10 x 10, 100 x 100, 1,000 x 1,000, or even beyond. Just remember to add the zero's!
Note: This only works with digits similar to the ones listed below.
Notice that they all have a 1 at the front and zero('s) behind them.
1) 10 x 10
2) 100 x 100
3) 1,000 x 1,000
This can continue to over 100 zero's per digit!
