The Four Rules for Negative Numbers
Maths: Edexcel A Level Pure Maths, topic 1.1.5
The Four Rules for Negative Numbers
You should be able to calculate: the sum, difference, product and quotient of negative numbers as well as positive numbers.
Calculating the sum
- When calculating the sum of two negative numbers, you go down the number scale away from 0.
Calculating the sum of a + and − number
Calculating the difference
Calculating the product
- When you multiply two negative numbers together, the product is positive.
- But when you multiply one negative number by one positive number the product is always negative.
Calculating the quotient
- When both numbers in the division calculation are negative, the quotient is positive.
- When one number in the division calculation is negative and the other is positive, the quotient is negative.
Some tips
- Calculating the sum and difference:
- If the calculation's function (the + or −) is the same as the sign in front of the 2nd number in the equation, the answer will be positive.
- If the calculation's function (the + or −) is different to the sign in front of the 2nd number in the equation, the answer will be negative.
- Calculating the product and quotient:
- If the numbers in the equation are either both positive or both negative, the answer will be a positive number.
- If one number in the equation is positive and the other is negative, the answer will be a negative number.
Test yourself on The Four Rules for Negative Numbers
Which of the following rules apply to calculations with negative numbers?