Explicație pas cu pas:
1. La primul nu stiu, dar ma mai gandesc
2. 28:7=4<27:3=9
35:5=7>20:10=2
32:8=4<24:4=6
42:7=6<63:9=7
72:8=9>36:6=6
32:4=8=40:5=8
3. 8×2=16
8×4=32
4×2=8
4×4=16
12×2=24
12×4=48
16×2=32
16×4=64
4.triplul lui 3 este 9
a:72=9
a=72×9
a=648
5. 7×8+(87-79):4=
56+8:4=
56+2=
58
24+5×(25:5:5-1)+25=
24+5×(1-1)+25=
24+5×0+25=
24+0+25=
49
3×2:6×[20+(54:9:2-2)]-20=
6:6×[20+(6:2-2)]-20=
6:6×[20+(2-2)-20
6:6×(20+0-20)=
1×20-20=
20-20
0
[(5×4+3×4):(9×8-8×8)]:4=
[(20+12):(72-64)]:4=
(32:8):4=
4:4=
1
