mathematicsfractions
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MATHEMATICS YEAR 4
FRACTIONS
NOTES(ADDING & SUBSTRACTING)
FRACTION: HOW TO ADD??
When the denominators are the same…
We have a rectangle that is cut into 4 pieces...
Each piece is and 2 pieces are
If we add , that would be…
14
24
4 41 2+
+ = = 34
When the denominators are different…
We need to find least common denominator (LCD)
For example,
The LCD for 2 and 3 is 6…
Change :
Change :
When the denominators are the same…
We have a rectangle that is cut into 6 pieces...
Each piece is . So,
HOW TO SUBTRACT??
16
56
- 26
56
= (5 pieces)
Take away 2 pieces,
So, 56
- 26
= 36
(3 pieces are left)
When the denominators are different…When the denominators are different…
FRACTIONSTASK : PROBLEM SOLVING (ADDING & SUBSTRACTING)
Instruction: Answer the problem solving questions and show the working steps. Students have to post their answers on teacher’s Wikispace, ‘mathsforfun’, at the discussion section.
Q1.Sally ate ⅛ of cake and her sister ate ⅜ of it. What fraction did they eat altogether?
Q2.Arif mowed 3/10 of the lawn and Tina mowed 5/10 of the lawn. How much of the lawn has been mowed?
Q3. May planted 1/3 of her vegetable garden in the morning and another 1/3 of it in the afternoon. What fraction of her garden was planted in one day?
Q4. Jill studied math for 2 3/4 hours and Spanish for 1 2/3 hours. What was her total study time?
Q5. Ashley made a muffin. She used 1 2/3 cups of white flour and 3 cups of whole-wheat flour. How much flour did she use in all?
Q6. Sidhu had 8 dollars. He spent ⅝ of his money on candy and
another ¼ of his money on soda. What fraction of his money did he spend altogether?
Q7. Maria collects 1 ¼ boxes of litter from the roadside. Amy collects 2 ¾ boxes. How many boxes of litter did they collect in all?
Q8. There are eight pieces of pizza. Roy ate 3/8 of the pizza for dinner. He ate 3/8 of the pizza for a bedtime snack. How much of the pizza is left?
Q9. Miss Lee brought 4 4/5 pounds of candy to school. The students in
third grade ate 2 ½ pounds of the candy. How much did Miss Lee have left?
Q10. A plumber needs 8 ¾ metres of pipe to repair a water line. He has only 4 ½ metres of pipe. How many more metres of pipe does he need?
Q11. Adam bought 2 1/5 pounds ground beef. His mother used 1 3/5 pounds to make hamburgers. How much of the ground beef was left?
Q12. All of William's school books weigh a total of 5 1/2 kilograms. If he take away his math book, the total weight drops to 2 1/2 kilograms. How much does William's math book weigh?
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