How_To_Be_Good_At_Math

NUMBERS • MULTIPLES 31

Here’s a way of finding the lowest common

multiple of three numbers.

Finding the lowest common multiple

Multiples of 4 are marked below the

number line. Look at the number 12.

It appears on both lines. So it’s a multiple

of both 3 and 4.

24 27 30 33 36 39 42 45 48

24 28 32 36 40 44

90

32 36 48

108

144 18

(^8156)
Common multiples of 2
and 6 are shaded white
Common multiples of 2
and 4 are shaded blue
Let’s find the lowest common
multiple of 2, 4, and 6. First,
we draw a number line showing
the first ten multiples of 2.
Now we draw a number line
showing the multiples of 4.
We find that 4, 8, 12, 16, and 20
are common multiples of 2 and 4.
When we draw a number
line of the multiples of 6, we
see that the first common multiple
of all three numbers is 12. So 12 is
the lowest common multiple of 2,
4, and 6.
Multiple mayhem
Which numbers are multiples of 8 and which are multiples
of 9? Can you find any common multiples of 8 and 9?
TRY IT OUT
Answers on page 319
48
Common multiples
of 2, 4, and 6 are
shaded yellow
Multiples and factors work together

• we multiply two factors together to
  get a multiple. So 3 and 4 are factors of 12,
  and 12 is a multiple of 3 and 4.

16

64

(^7227)
The next number that’s a
multiple of both 3 and 4 is 24
The arrow means that there are
more multiples of both 3 and 4
MULTIPLES OF 4
FROM 1 TO 50
The lowest common multiple
of all three numbers is 12
2 4 6 8 10 12 14 16 18 20 22
MULTIPLES OF 2
MULTIPLES OF 4
MULTIPLES OF 6
24
4 8 12 16 20 24
6 12 18 24
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0
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