12.
2 and a half plus 2 and a half plus 10 plus 10 = 25
10
2+4+8+2+10+6 = 6+8+2+10+6 = 14+2+10+6 = 16+10+6 = 26+6 = 32
30. 2+3+5=10, 4+6=10, and 2+4+1+1+2=10.
18 + 2 + 10 = 30
4 + 2 + 10 + 50 = 66
2 + 10 + 250 + 1250 = 1512
-2 + 10 - 8 + 4 - 3 + 2 = 3
(10 + 1) x 10/2
61
10
16 plus 10 plus 8 plus 6 plus 2 is equal to 42.