90
45 and 30
???
15 and 10 if you multiply them. 140 and 10 if you add them. 160 and 10 if you subtract them. 1500 and 10 if you divide them.
63
31
23
70
40
???
50
That depends how you want to "combine" them: add, subtract, multiply, etc.
15 and 10 if you multiply them. 140 and 10 if you add them. 160 and 10 if you subtract them. 1500 and 10 if you divide them.
78
The two numbers are -2 and -15
i do not no
It is: (15-7)*(12-9) = 24
13 and 2
63