NOTES
,Study Unit 1: Numbers and Working with Numbers
1.1 Priorities and Laws of Operations:
B O D M A S or B E D M A S
+; −;×;÷
Adding and Subtracting
All numbers can be represented on a number line.
Numbers greater than zero are .
Numbers less than zero are .
The number zero is neutral.
On a number line, numbers get greater as you move right.
Therefore 5 is bigger than 3 (5>3).
Numbers get smaller as you move left.
Therefore -5 is smaller than -3 (-5<-3).
Exercise 1
1. 53 5. 4 p 3q
2. 4x 6x 6. 3 (2)
3. 57 7. 1d (3d )
4. 6ab 2ab 8. 3 (6) (2)
Any integer and its additive inverse add up to zero.
1
,Exercise 2
1. 22
2. 454
3. 5 21 10 21 5
Multiplying and Dividing
Note: Multiplication can be indicated in 3 different ways
- A multiplication sign
- A point
- Brackets
Note the following:
The product of any number with zero is zero.
The product of any number with 1 is the number.
The product of any number and its inverse is 1.
When multiplying always remember:
(+) × (+) = (+) (+) × (−) = (−)
(−) × (−) = (+) (−) × (+) = (−)
The rules for division are the same as the rules for multiplication.
It is preferable to turn a into a fraction.
(+) (+)
= (+) = (−)
(+) (−)
(−) (−)
= (+) = (−)
(−) (+)
2
, When squaring or cubing integers, follow the same rules you use for multiplication.
Squaring a number involves multiplying the same number twice.
Cubing a number involves multiplying the same number three times.
Exercise 3
1. (3)(2)
2. 57
3. (3) 2 (4)
4. −(2)(4)
−4
5. 2
6. 2(−4)2 + 2(−3) − 12
7. (−2)3 − 3(3) + 2
−2(5)−8
8. −4(5−3)
Now we will combine the rules above with BODMAS
Exercise 4
1. 5 ×4 ÷2−3 ×2+6 ÷3
2. (5 × 4 ÷ 2 − 3 × 2 + 6) ÷ 3
3. 3 − 52 + 2 × 4 + (−3)2 − √16 + 9 ÷ 5
3