17p - 3p - 2n + 5n
x/11-y/8=-2
x/2-y/4=3
15a - 6b + 4a + 12b
8.1 / 0.9 + 0.4^3 / 0.8 x 30
2/3 x 3
xmas3x
x+3x
15x5
5m + 6 + 3m + 10