Find the value of -9-(-10) using the number line:
-1
-2
+1
+2
-9-(-10) = -9+10
=> Move 10 steps towards right from -9 and you will reach +1.
Add using number line:
(1) 5 and 3
(2) 6 and 2
(3) (−3) and (+5)
(4) 8 and (−12)
(5) (−7) and 5
(6) 10 and (−14)
(7) (−5) and (−2)
(8) (+6) and (−9)
(9) (−4) and (−1)
(10) 1 and (−5)