30=3 times 10 right so 30 times 30=3 times 10 times 3 times 10=3 times 3 times 10 times 10 we know that 3 timmes 3=9 and 10 times 10 is 100 so 30 times 30=9 times 100=900
Here is a way I was thought with zeroes, first do 3x3 which is 9 then since there are 2 zeroes you tack on 2 zeroes at the end to get 900. Hope this helped.
