Each of the 100's ends in 2 zeros, and 2 + 2 = 4, so we might expect that 100 times 100 isequal to a 1 followed by 4 zeros, 10000 = 10,000. Is that right? ... To multiply 73 time 100,000, for instance, just put 5 zeros (the number of zeros in 100,000) after the 73: 73 x 100,000 = 73(00000) = 7,300,000.