26 + 21 = 47
-26
26 less than 21 is negative 5
-3x + 10x - 5 + 26 = 7x + 21
228
its like subtracting. so 26-5=21, -26+5=-21 it seems like your subtracting
26 - 21 = 5 or 24 - 23 = 1
13 + 16 + 18 + 20 + 21 + 26 + 27 + 27 + 28 + 36 + 39 + 42 + 43 = 356
15x26=390
5+21= 26 26/7= 3.7 3.7-6= -2.3
26/63
2/3 +4/7 = 14/21 + 12/21 = 26/21 = 1 5/21
26 + 26 + 26 + 26 = 4 x 26 = 104