Integers – Multiplication of Integers.
CBSE CLASS 7 MATHEMATICS
INTEGERS – Chapter 1
Multiplication of Integers:
I. Multiplication of a positive and a negative Integer:
While multiplying a positive integer and a negative integer, we multiply them as whole numbers and put a minus sign (-) before the product. We thus get a negative integer.
Examples:
1. 4 x (-8) = -32
2. (-5) x 3 = -15
3. 9 x (-2) = -18
II. Multiplication of two Negative Integers:
We multiply the two negative integers as whole numbers and put the positive sign before the product. We can say that the product of two negative integers is a positive integer.
Examples:
1. (-10) x (-12) = 120
2. (-15) x (-6) = 90
3. (-3) x (-4) = 12.
III . Product of three or more Negative Integers:
If the number of negative integers in a product is even, then the product is a positive integer; if the number of negative integers in a product is odd, then the product is a negative integer.
Examples:
1. (-4) x (-3) x (-2) = -24
2. (-4) x (-3) x (-2) x (-1) = 24
3. 9 x (-2) x (-3) = 54
Practice Problems:
Find each of the following products:
1. (-8) x 7
2. (-75) x (-2)
3. (-4) x 0 x (-2)
4. 3 x (-8) x (-1)
5. (-5) x (-2) x (-1)
All the sums are very useful