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JSS2: MATHEMATICS - 1ST TERM

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



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

For 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

Evaluation Questions:

1. Find all the factors of 48

View Answer

2. Find the factors of 100 that are

i. Odd numbers
ii. Even numbers
iii. Multiples of 2
iv.  Multiples of 5

View Answers

3. Write down the first six multiples of 7

View Answer

4. Express the following numbers as a product of prime factors.

a. 64
b.  120    
c.  500    
d.   980

View Answers

5. Express  24 x 36  as a product of its prime factors in index form.

View Answer

6. Find the common factors of the following:

a. 16 and 30
b. 36 and 50

View Answers

7. Find the HCF of:

a. 4 and 12
b. 9, 18 and 54
c. 36 and 81

View Answers

8. Find the HCF of

a. 22 x 32 x 53 x 7  and 24 x 35 x 5 x 72

b. 52 x 73  and  53 x 74

View Answers

9. Find the first three common multiples of

a. 5 and 6
b. 2,  3  and 4

View Answers

10. Find the LCM of

a. 12, 18 and 36
b. 5,  10, and 15
c. 52 x7 x 11,    2 x 3 x 5  x 11
d. 23  x 3  x 53;        2 x 32 x  52;      23  x 33  x  5 x 72

View Answers

Responses

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All factors of 48 are;

1, 2, 3, 4, 6, 8, 12, 16, 24, and 48

i. Odd numbers – 1, 5, 25

ii. Even numbers – 2, 4, 10, 20, 50 and 100

iii. Multiples of 22, 4,10, 20, 50 and 100

iv. Multiples of 5 – 5, 10, 20, 25, 50 and 100

The first six multiples of 7 are

:-  7, 14, 21, 28, 35, and 42

a. 64 = 2 x 2 x 2 x 2 x 2 x 2 

b. 120 = 2 x 2 x 2 x 3 x 5

c.  500 = 2 x 2 x 5 x 5 x 5

d. 980 = 2 x 2 x 5 x 7 x 7

24 x 36 = 25 x 33

a. Common factors of 16 and 30 = 1,2

b. Common factors of 36 and 50 = 1,2

Find the HCF  of

a. HCF of 4 and 12 = 4

b. HCF of 9, 18 and 54 = 9

c. HCF of 36 and 81 = 9

a. HCF of 22 x 32 x 53 x 7  and 24 x 35 x 5 x 72 = 22 x 32 x 5 x 7 = 1260

b. HCF of  52 x 73  and  53 x 74 = 52 x 73= 8575

a. The first three common multiples of 5 and 6 = 30, 60, 90

b. The first three common multiples of 2, 3, and 4 = 12, 24, 36

a. The LCM of  12, 18 and 36 = 36

b. The LCM of  5,  10, and 15 = 30

c. The LCM of  52 x7 x 11,    2 x 3 x 5  x 11 = 2 x 3 x 52 x 7 x 11

d. The LCM of 

23  x 3  x 53        

2 x 32 x  52     

23  x 33  x  5 x 7

=23 x 3x  53 x 72

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