39, because when you subtract 20 you get forty but when you subtract another number, you get 39.
21/60 - 1/15 = 17/60 To subtract fractions, make them have the same denominator (bottom number) by converting them to equivalent fractions (usually with the lowest common multiple of the denominators) and then subtract the numerators (top numbers). So for 21/60 - 1/15: lcm(15, 60) = 60: 21/60 = 21/60 1/15 = 4/60 ⇒ 21/60 - 1/15 = 21/60 - 4/60 = 17/60
-60
50.3625 in DMS form is 50.21.45 50 is the D part. Subtract 50 to get 0.3625. Multiply by 60 to get 21.75. 21 is the M part. Subtract 21 to get 0.75. Multiply by 60 to get 45. 45 is the S part.
Subtract 21. x + 21 - 21 = x.
Only once, because after that you do not have 60 to subtract from!
21
How many times do you subtract 2 from 11?
54
23
100 - 21 = 79
29
The difference between 275 and 215 is 60.