Show:
add
sub
x and y
9+_=
9-_=
120

8+8=

a. 16

b. 14

c. 8

A

120

7-1=

6

120

x-2=y

a. 7 5

b. 7 9

a

120

9+_=12

3

120

9-2=

7

228

7+1=

8

228

8-1=

7

228

x5- 6= y

7 9

228

9+9=

18

228
9-8=

1

328

8+7=

15

328

7-2=

5

328

x1+y6=z

remove the z

328

9+1=

10

328

9-7=

2

428

9+9=

18

428

7-6=

1

428

5-x=y

2 3

428
9+2=

11

428

9-3=

6

528

8+2=

10

528

1-1=

0

528

a-x=9

replace the a with the number 12

528

9+4=

13

528

9-4

5