HCF&LCM by tree method🌳

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Ppraew💗

Junior High 1

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2026.07.15 公開

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ページ1:

HCF by Tree Method
Example 72
72
108
9
108)
2×3×3×2×2
2
36
129
3
= 2³× 3²
3 12
34 33
34
22
22
2
2
3×2×2×3×3=2×3
The tree method is way to find HCF by "breaking
each number into its prime factors using a factor
tree.
72:23x32
108:22×33
2
2
HCF = 2 x3
2
===
1 Draw a factor tree for each number.
36
Ⓒ Write each number as a product of its prime factors
(③ Identify the common prime factors and choose the
smallest power clowest exponent) of each.
④ Multiply these common prime factors together. The resolt
is the HCF

ページ2:

LCM by tree Method
Example 72, 108
72
=
23³× 3²
2
108
=
22 × 33
LCM
=
2³× 3,3
=
216
Write each number as a
prime factors
product of its
© Choose the highest power (greatest exponent)
of each primer factor.
③ multiply them together. The result is the LCM
Sweet
HIKING MAP

ページ3:

Example 2,8 and 12
2
8
2
2=2
8=23
2
12 = 3×2²
3
8:2
8 · 2 3
d
3
Find HCF & LCM
2
12
12: 3×2
2
2
HCF : Choose the common prime
factors with the smallest
power.
• Common prime factor: 2
2:2
: 2'
• Smallest power of 2 :
HCF = 2
LCM: Choose all prime factors with the highest powers.
Highest power of 2 is 23
Highest power of 3 is 3'
3
LCM =
2× 3
= 24

ページ4:

Key Denfinitions for Tree Method
• HCF:
The largest number that divides all the given
numbers exactly.
In the tree method: Choose the common
prime factors with the smallest powers
(lowest exponents), then multiply them together.
。 LCM:
The smallest number that is a multiple of
all the given numbers.
In the tree method: Choose all the prime
factors with the highest powers (greatest exponents),
then multiply them together
Remember
•HCF → Common factors + Smallest powers
• LCM → All factors + Highest powers
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