The big one is 30*20 which is 600 and the tiny one is 2*4 which is 8
You basically break down the number depending on how many numbers are in a whole and make a box for that number example 21* 53
20 + 1
50 1000 | 50
+ -----------------
3 60 | 3
After you get all your products you add them all up to get your answer
1000
50
60
+ 3
---------
1113 < your final answer