Question

Add the following integers:
i) 7 and -10 using the number line
ii) -5 and -4 using the number line
iii) 30 + (-49) + 45 + (-25)
iv) -144 + 25 + ( -36) + 81

Answer 1

i) We mark 7 on the number line and move backwards by 10 steps on the number line shown as follows:

ii) Here, we start at -5 and move back 4 steps as shown:
iii) We add the positive integers and negative integers separately, and then perform the final calculation:

30 + (-49) + 45 + (-25)
= (30+45) + [(-49) + (-25)]
= 75 + (-74)
= 1

iv) Similar to the previous problem, we group the terms together:

-144 + 25 + ( -36) + 81
= (25 + 81) + [(-36) + (-144)]
= 106 + (-180)
= -74