Show:
adding 3 numbers
2 digit by 2 digit
2 digit by 1 digit
subtraction
what number
100

2+2+4

8

100

12+24

36

100

14+5

19

100

8-4

4

100

2 tens 5 ones

25

200

5+2+1

8

200

72+27

99

200

22+6

28

200

12-6

6

200

4 tens 1 one

41

300

8+1+1

10

300

44+44

88

300

54+1

55

300

19-2

17

300

8 tens 

80