15 more than 12 is 27, this is done by adding 15 to 12 finding the sum of 27. This can be displayed algebraically with 15+12=27.
27
27 - 12 = 15
9, 15, 21, 25 and 27 aren't .. because they have more than two divisors.
15
27
42-15=27
12 + 15% = 12.1512% + 15% = 27%13.8 is 15% greater than 12.
27 + 95 = 122
15 is more than 2.
15 more than -3 = 12
45 + 27 = 72