Addition
15+15=
30
30-15=
15
9x9=
81
12/6=
2
9x9=108
False, it's 81.
90+90
180
120-60=
60
10x10=
100
20/10=
2
144/12=12
True
35+35=
70
32-16=
16
20x20=
400
20/5=
4
36/6=5
False, it is 6.
240+240=
480
250-125=
125
400x4=
1600
40/4=
10
99/11=9
True
136+136=
272
272-136=
136
500x9=
3500
100/25=
4
180+180=340