Week 3 – Jss 2 First Term Mathematics Lesson Notes

WEEK 3            HIGHEST COMMON FACTOR AND LOWEST COMMON FACTOR

 EXAMPLE 1: Find the L C M of 18 and 24
Solution:
METHOD 1                        METHOD 2    
2    18    24                    18 = 2 ×3 ×3
2    9    12                    24 = 2 ×2 ×2 ×3
2    9    6                    L C M = 2 ×2 ×2 ×3 ×3
3    9    3                        = 72
3    3    1
    1    1
L C M = 2 × 2 × 2 × 3 × 3 = 72    

 Example 2: Find the L C M of 72 and 90
Solution:                
METHOD 1                    METHOD 2        
2    72    90                72 = 2 X 2X 2 X 3 X 3
2    36    45                90 = 2X 3 X3 X 5
2    18    45                L C M = 2 X 2 X 2 X 3 X 3 X 5
3    9    45                    = 360
3    3    15
5    1    5
    1    1
2 x 2 x 2 x3 x 3 x 5 = 360

 Example 3: Find the H C F of 72 and 96
Solution: find the prime product of the number and pick the common ones
72 = 2 * 2 * 2 * 3 * 3
96 = 2 * 2 * 2 * 2 * 2 * 3
H C F = 2 * 2 * 2 * 3
= 24

 SQUARE AND SQUARE ROOT

 “Square” is the product of two equal terms example N * N = N²
Example 1: Find the square of 14 and 21
Solution:
14 * 14 = 196         (b) 21 * 21 = 441.
Square Root: A number that when multiply by itself equals a given number.
Example 2: find the square root of 144
Solution:
Using a prime factor method (method 1)    Factor pairs method (method 2)
2    144                    144 = 1 *144
2    72                     = 2 * 72
2    36                     = 3 * 48
2    18                     = 4 * 36
3    9                     = 6 * 24
3    3                     = 8 * 18
    1                      = 9 * 16
Therefore (2 * 2) * (2 * 2) * (3 * 3) = 2* 2 * 3 = 12      = 12 x 12
ASSESEMENT

1. Find the square of the following (a) 25, (b) 40 and (c) 132
2. Find the square root of the following (a) 6400 (b) 16900 (c) 1296

 Assignment: essential mathematics text book for J SS 2 PAGE 10 EXERCISE 1.6 NO 2 (e, f) , NO 6 (b, c)