First multiply 700 and 300
700 x 300= 210000
Now count the zeros in the number.
So the product of 700 and 300 have 4 zeroes.
Another way to do this is just count the zeroes under 700 and 300.
When you multiply any two numbers that have zeroes the zeroes will practically add together.
For example. 10 x 10 =100, they had one zero and the total has 2 zeroes.
Or 30 x 40=1200 they had one zero and the total has 2 zeroes.