It is: 1318 plus 19 = 1337
18 and 19
They are: -18+(-19) = -37
18, 19, 20
18, 19, 20
It is: 1318 plus 19 = 1337
37 - at least it was when I went to school !
18 and 19
54
They are: -18+(-19) = -37
18, 19, 20
18, 19, 20
17, 18, and 19
41 - 9 = 32
17+18+19
18+19+20+21+22
18 + 19 + 20 = 57