Post on 22-Dec-2015
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N4 Multiplying and dividing negative numbers
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Negative numbers in context
There are many real life situations which use negative numbers.
Temperature
Balance -$34.52
Bank balances
Games with negative scores.
Measurements taken below sea level
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–3 + –3 + –3 + –3 + –3 =
0–3–6–9–12
–3
–15
–15
5 × –3 = –15
A positive number × a negative number = a negative number
Multiplying and dividing integers
–3–3–3–3
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–4 × –6 =
0
– –6
6
– –6
12
– –6
18
– –6
24
24
A negative number × a negative number = a positive number
Multiplying and dividing negative numbers
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When multiplying negative numbers remember:
Rules for multiplying and dividing
Dividing is the inverse operation to multiplying.
When we are dividing negative numbers similar rules apply:
+ × + = +
–+ × = –
–+× =–
– +× =–
+ ÷ + = +
–+ ÷ = –
–+÷ =–
– +÷ =–
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3 × –8 ÷ = 1.5–16
–4 × –5 × –8 = –160
–7 × = 175–25
÷ –90 = –6540
–36 ÷ = –4
47 × = 141
42 ÷ = –6
–3 × 8 = –24
Multiplying and dividing integers
Complete the following:
–7
× –8 = 96–12
3
–72 ÷ –6 = 12
9
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Number spiral
3
–7–4
×2–8
–2 –10 ÷ –5
2
× –1
–2
+ 86÷ –2–3
× 5
–15
+ 4 –11– 5
–16+ 16
0
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