Show:
Adding up to 5
Subtracting up to 5
Adding up to 10
Subtracting up to 10
Multiplying
100

19

+1

100

21

-1

100

14

+6

100

26

-6

100

20 x

1
200

18

+2

200

22

-2

200

13

+7

200

27

-7
200

1 x

20

300

17

+3

300

23

-3

300

12

+8

300

28

-8

300

10 x

2

400

16

+4

400

24

-4

400

11

+9

400

29

-9

400

5 x

4

500

15

+5

500

25

-5

500

10

+10

500

30

-10

500

4 x

5