1x1 = 1
10x10 = 100
100x100 = 10,000
1,000x1,000 = 1,000,000
10,000x10,000 = 100,000,000
100,000x100,000 = 10,000,000,000
1,000,000x1,000,000 = 1,000,000,000,000
10,000,000x10,000,000 = 100,000,000,000,000
100,000,000x100,000,000 = 10,000,000,000,000,000
1,000,000,000x1,000,000,000 = 1,000,000,000,000,000,000
Simply count up all the zeroes then put a one in front.