Explicație pas cu pas:
15 = 15
21 > 4
36 > 18
30:5=6
18:3=6
72:8=9
36:6=4
12:6=2
3×9=27
14+3=17
9×7=63
18-9=9
63:7=9
19+5=24
21:7=3
4×8=32
16:2+9×2=8+18
=26
26+9×6=26+54= 80
80-35:5 =80-7=63
72:8×4=9×4=36
28+4=32
28-4=24
28:4=7
