My grandson is asking this question and I really don't know how to assist him. He is in another town and called me...so here goes.
8+4=12, but 20+4 does not = 30
Here are the numbers he gave me over the phone and the order in which they are assembled on his sheet:
8 12
20 30
2 3
10 15
I'm not sure where to go with this or even what the RULE is/are, but thought that you might.
Here's one way to see the pattern:
8 plus half of 8 = 12
20 plus half of 20 = 30
2 plus half of 2 = 3
10 plus half of 10 = 15
or
x = 12
x = 30
x = 3
x = 15
or
x 1 = 12
x 1 = 30
x 1 = 3
x 1 = 15
or
8 x 1.5 = 12
20 x 1.5 = 30
2 x 1.5 = 3
10 x 1.5 = 15
Edwin