(a) (-7) – 8 – (-25)
= (-7) – 8 + 25
= -15 + 25 = 10
(b) First, let’s add all the positive numbers and all the negative numbers separately
(-13) + 32 – 8 – 1
= 32 - 22
= 10
(c) (- 7) + (- 8) + (- 90)
= – (7 + 8 + 90)
= -105
(d) 50 – (-40) – (-2)
= 50 + 40 + 2
= 92
Complete the drawing shown in Fig. 9.14 to indicate where the free ends of the two wires should be joined to make the bulb glow