Back to Course

JSS2: MATHEMATICS - 1ST TERM

0% Complete
0/0 Steps
  1. Properties of Whole Numbers I | Week 1
    4Topics
    |
    2 Quizzes
  2. Properties of Whole Numbers II | Week 2
    4Topics
    |
    2 Quizzes
  3. Properties of Whole Numbers III | Week 3
    4Topics
    |
    1 Quiz
  4. Indices | Week 4
    2Topics
    |
    1 Quiz
  5. Laws of Indices | Week 5
    5Topics
    |
    1 Quiz
  6. Whole Numbers & Decimal Numbers | Week 6
    4Topics
    |
    1 Quiz
  7. Standard Form | Week 7
    3Topics
    |
    1 Quiz
  8. Significant Figures (S.F) | Week 8
    4Topics
    |
    1 Quiz
  9. Fractions, Ratios, Proportions & Percentages I | Week 9
    6Topics
    |
    1 Quiz
  10. Fractions, Ratios, Proportions & Percentages II | Week 10
    4Topics
    |
    1 Quiz
  11. Fractions, Ratios, Proportions & Percentages III | Week 11
    3Topics
    |
    1 Quiz
  12. Approximation & Estimation | Week 12
    1Topic
    |
    1 Quiz
Lesson Progress
0% Complete

The lowest common multiple of two or more numbers is the lowest multiple they have in common. 

Example:

The multiples of 2 are  2, 4, 6, 8, 190, 12, 14, 16, 18……

The multiples of 3 are 3, 6, 9, 12, 15, 18 …….

The common multiples of 2 and 3 are 6, 12, 18, ……

The lowest common multiple of 2 and 3 is 6;

Example

Find the LCM of 

a. 3, 7 and 10

b. 2, 3 and 4

c.

23 x 32 x 5

22 x 3 x 5

d.

24 x 32 x 5 x 7 x 112   

23 x 5 x 73 x 11

22 x 33 x 5 x 72 x 11

Solution

a.

1st Method

lcm

LCM  = 2 x 3 x 5 x 7

= 6 x 35

=  210

2nd Method: Find the prime factors of the given numbers.

Screen Shot 2021 09 21 at 2.15.21 PM

3 = 1 × 3

7 = 1 × 7

10 = 2 × 5

L.C.M. = 1 x 2 x 3 x 7 x 5

= 210

b.

Screen Shot 2020 11 21 at 9.13.15 PM

LCM  of 3 and 4 = 2 x 2 x 3 = 12

c.

23 x 32 x 5

22 x 3 x 5

In this case, compare the index (power) of numbers with the same base. The numbers with greater power (index) are the common multiple.

23 x 32 x 5

22 x 3 x 5

= 23  x   32   x   5

LCM   =   23   x  32   x  5

d.

24 x 32 x 5 x 7 x 112 

23 x 5 x 73 x 11

22 x 33 x 5 x 72 x 112

Screen Shot 2020 11 21 at 9.19.04 PM

LCM   =   24   x  33   x  5  x  73   x  112

back-to-top
error: