Tuesday, 29 March 2022

Sangster FL class, March 29

 - math test (fraction and some of the financial literacy materials) on Friday, April 1


March 29, 2021

Problem solving with fractions

a.     2 5/8 + 1 1/8 = 3 + (5/8 + 1/8)

Answer: 3 6/8, reduce to 3 ¾

 

b.     4 ¼ + 2 ¾ = 6 4/4 = 6 + 1 = 7Kg

 

c.     3 2/5 + 1 1/5 = 4 3/5 Km

 

d.     2/3 + ½ = (2 x 2/3) + (3 x ½)

 

= 4/6 + 3/6

= 7/6 = 1 1/6

 

e.     3 3/5 – 1/3 

Common denominator between 3 and 5 = 15

Change these fractions with denominator of 15

3 3/5 = 3 (3x3)/(3x5) = 3 9/15

1/3 = (1x5)/(3x5) = 5/15

 

3 9/15 + 5/15 = 3 4/15Kg

 

f.      4 2/3 – 1 1/5

Common denominator between 3 and 5 = 15

Change these fractions with denominator of 15

 

4 2/3 = 4 (5x2)/(5x3) = 4 10/15

1 1/5 = 1 (1 x3)/(3x5) = 1 3/15

 

4 10/15 – 1 3/15 = 3 7/15 litres left

 

 

 

 

 

 

 

 

g.     5 ¼  – 3 7/12 

Common denominator between 4 and 12 = 12

Change these fractions with denominator of 12

 

5 ¼ = 5 (1x3)/(3x4) = 5 3/12

5 3/12 – 3 7/12 = 4 15/12 – 3 7/12 = 1 8/12

(the fraction part, 3/12 – 7/12. I need to borrow from

The whole number so that the first fraction is larger

So that I can subtract

5 3/12 = 4 15/12

(1 whole = 12/12)

5 – 1 = 4 (whole number part)

Add 12/12 to 3/12 = 15/12 (so that I can subtract 7/12

 

 

1 8/12 = 1 2/3 Kg left


h. a.     9/10 – 5/6 

Common denominator between 10 and 6 = 30

Change these fractions with denominator of 30

 

9/10 = (9x3)/(3x10) = 27/30

5/6 = (5x5)/(5x6) = 25/30

 

27/30 – 25/30 = 2/30 left = 1/15 left

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