-21
13:21
21/13 ≈ 1.62 = 162% or work like this: 21/13 = 13/13 + 8/13 where, 13/13 is a whole which is 100% and 8/13 ≈ .62 which is 62%, so 21/13 = 13/13 + 8/13 = 100% + 62% = 162%
21 - 8 = 13
n + 13 = 21. n = 21 - 13
13/7 of 21 is 39.
21 x 13 = 273
13/21
If p is 13 then 13-21 = -8
21
21 and 13.. 21-13=8 21+13=34 34/2 = 17,+4 = 21... 34-21 = 13
One possibility is (21 - 21) * 13 + 24 = 24