20 +
20 +
20 +
20 +
20 +
=
100
20 + 20 is 40
40 + 20 is 60
since we know 20 + 20 is 40 and we have 2 20's left we can say
40 + 60 to make things easier
so the answer is 100
20 +
20 +
20 +
20 +
20 +
=
100
20 + 20 is 40
40 + 20 is 60
since we know 20 + 20 is 40 and we have 2 20's left we can say
40 + 60 to make things easier
so the answer is 100