You add 10 to -7 to get 3.
7
3
10
-25
4
The number is 21. 21 ÷ 3 = 7 7 - 3 = 4
256
10
3
x-7 = 3 add 7 to both sides of equation x -7+7 = 3 +7 X = 10
Of course, the answer will be -3 + -4 Because 4 and 3 is 7 so when you add the - sign it is now -7.