Матем 81-(52-9)= (38+58)-18 6×3:2= 2×6:4= 18:6×2= 21:7×9=

1) 81-(52-9)=38

52-9=43

81-43=38

2) (38+58)-18=78

38+58=96

96-18=78

3) 6×3:2=9

6×3=18

18:2=9

4) 2×6:4=3

2×6=12

12:4=3

5) 18:6×2=6

18:6=3

3×2=6

6) 21:7×9=27

21:7=3

3×9=27