21h-10h+16-9+14h+5
Collect the like terms. Like terms are numbers that have the same variable (like x, y, a, n...)
Like terms are:
21h, -10h, +14h
And
16, -9, +5
So add/ subtract the like terms
21h - 10h + 14h= 25 h
16 - 9 + 5 = 12
You can’t add 25h by 12 so your final answer is
25h+12