Pre Algebra - Lesson 3: Adding and Subtracting Negative Numbers

Exercises:

Question 1
Use a number line to work out the following calculations:

(a) -4 + 6 =__
(b) -5 + 8 =__
(c) -1 + 3 =__
(d) -4 + 7 =__
(e) 2 + (-3) =__
(f) -1 + (-4) =__
(g) -2 + (-3) =__
(h) -6 + 6 =__
(i) -7 + 4 =__
(j) -6 + 2 =__
(k) -7 + 2 =__
(l) 5 + (-5) =__

Question 2
Use a number line to calculate:

(a) 4 - 6 =__
(b) 5 - 7 =__
(c) 2 - 4 =__
(d) -1 - 1 =__
(e) -3 - 2 =__
(f) -4 - (-1) =__
(g) 3 - (-4) =__
(h) 5 - (-6) =__
(i) 8 - 12 =__
(j) -5 - (-1) =__
(k) 4 - 9 =__
(l) -4 - (-4) =__

Question 3
Fill in the missing number in each of these equations:

(a) 4 +__ = 1
(b) 3 -__ = -6
(c) -6 +__ = -7
(d) __+ 7 = 2
(e) __- 7 = -8
(f) 4 -__ = 7

Question 4
Make number lines for each section (S._).

(S.a) 10, 8, 6, 4,
(S.b) -10, -7, -4, -1,
(S.c) 19, 14, 9, 4,
(S.d) -1, -3, -5, -7,
(S.e) -20, -16, -12, -8,
(S.f) -5, -10, -15, -20,
(S.g) 18, 15, 12, 9,
(S.h) -16, -12, -8, -4,

Question 5
Overnight, the temperature dropped from 5 ºC to -14 ºC.
By how many degrees did the temperature fall?

C: 5º__-14º=__
A:The temperature fell __ degrees.

Question 6
One day the level of the water in a river was 30 cm above its average level.
One week later it was 12 cm below its average level.
How far did the water level drop in the week?

C:30cm__12cm=__
A:The water level dropped __cm in the week.


Question 7
A chest of treasure was hidden in the year 64 BC and found in 284 AD.
For how long was the chest hidden?

C:64__284=__
A:The chest was hidden for __ years.