Lesson 1 of 4 · Grade 7 Mathematics
Integers
15 min
Integers are whole numbers and their negatives: ..., -3, -2, -1, 0, 1, 2, 3, ...
On the number line
Numbers increase to the right. -5 is less than -2 because it is further left.
Adding and subtracting
- 5 + (-3) = 5 - 3 = 2
- -4 + (-6) = -10
- -4 + 6 = 2
- 3 - (-2) = 3 + 2 = 5 (subtracting a negative is adding)
Multiplying and dividing
- Same signs give a positive: (-3) x (-4) = 12; (-12) ÷ (-3) = 4
- Different signs give a negative: (-3) x 4 = -12; 15 ÷ (-5) = -3
Real life
Temperatures: if it is -2 °C at night and rises by 7 °C, it becomes 5 °C.
Money: a debt can be written as a negative number.
Key points to remember
- Integers include negative numbers and zero
- Subtracting a negative = adding
- Same signs multiply to positive
- Different signs multiply to negative
Test yourself
