Explicație pas cu pas:
a)13,7,20.
13+7=20
7+13=20
20+7=27
7+20=27
20+13=33
13+20=33
13-7=6
20-13=7
20-7=13
b)54,36,18.
54+36=90
36+54=90
36+18=54
18+36=54
54+18=72
18+54=72
54-36=18
54-18=36
36-18=18
c)35,42,77.
35+42=77
42+35=77
42+77=119
77+42=119
77+35=112
35+77=112
42-35=7
77-42=35
77-35=42