1

2

40 + 30 = 70

4 + 3 = 70

400 + 300 = 700

3

40 - 30 = 10

4 - 3 = 10

400 - 300 = 100

4

46 + 30 = 76

4 + 3 = 76

5

46 - 30 = 16

4 - 3 = 16

6

16 + 11 = 27

16 + (10+1) = 27316 + 11 = 327

7

16 + 9 = 2516 + (+10-1) = 25

316 + 9 = 325

8

16 - 11 = 5

16 – (-10-1)= 5

9

16 - 9 = 716 - (-10+1) = 7

316 - 9 = 305

10

16 + 21 = 27

16 + (20+1) = 27

11

56 - 21 = 35

56 - (20-1) = 35366 - 21 = 345

12

2 x 10 = 204 x 100 = 400

7 x 1000 = 7000

13

2 x 60 = 1204 x 300 = 1200

7 x 6000 = 42000

14

27 x 10 = 27046 x 100 = 4600

79 x 1000 = 79000

15

276 x 10 = 2760

467 x 100 = 46700

793 x 1000 = 793000

16

20 x 50 = 1000

400 x 70 = 28000

17

24 x 2 =48

4 x 2 = 82 x 2 = 4

18

25 x 2 =50

2 x 2 =44 +1 = 5

19

20 / 2 = 10

600 / 2 =300

20

42 / 2 = 21

4/2= 2

2/2= 1

21

642 / 2 = 3216/2= 24/2= 1

2/2= 1

22

156 + 200 = 356

1 + 2 = 356

23

856 - 300 = 556

8 - 3 = 5

24

856 - 101 = 957

856 +100 +1 = 957

25

856 + 201 = 1057

856 +200 +1 = 1057