Show:
adding 10s
adding 3 numbers
adding 1 digit to 2 digits
subtraction
double digit addition
100

10 + 10 =

20


100
4 + 4 + 1=

9


100

20 + 4 = 

24

100

2 - 1

1

100

10 + 11 = 

21

200

20 + 10 = 

30


200

5 + 5 + 3

13

200

30 + 3

33

200

4 - 2 = 

2

200

30 + 12

42

300

40 + 20 = 

60

300

6 + 6 + 2

14

300

30 + 6 = 

36

300

6 - 1 =

5

300

51 + 23

74

400

30 + 50 =

80


400

10 + 2 + 4

16

400

51 + 9 = 

60
400

8 - 2

6

400

56 + 22

78

500

80 + 20 = 

100


500

15 + 2 + 3

20

500

22 + 7

29

500

12 - 6 = 

6

500

46 + 26

72