Back to: Mathematics Primary 3
Addition And Subtraction Of Fraction With The Same Denominator
Add and Subtract Like Fractions.
Like Fractions are fractions with the same denominator.
Example 1: Pablo spent 3/5 of an hour on a jigsaw puzzle. Conrad spent 1/5 of an hour on the puzzle. How much time did they spend working on the puzzle in all?
You need to add 3/5 and 1/5.
Note this: To add fractions with the same denominators, add the numerators and keep the same denominator.
3/5 + 1/5
Add and Subtract Mixed Numbers.
Example 3: Tim is painting a backdrop for the school play. He mixed 22/4 gallons of blue paint and 11/4 gallons of red paint to make dark purple. How many gallons of dark purple paint did Tim make?
Add. 22/4 + 11/4
(2 + 1) 2 + 1/4 = 33/4
So, Tim made 33/4 gallons of dark purple paint.
Subtracting mixed numbers with like denominators is similar to adding mixed numbers.
Add and Subtract Unlike Fractions.
Example 4: Find 1/2 + 1/4
Step 1: Check the denominators (Since they are different)
Step 2: Check if the denominators can divide each other. If they can; pick the greater number but if they cannot; multiply them.
Step 3: Continue with the working as outlined in the previous topic.
1/2 + 1/4
2 + 1 /4 = 3/4
Example 5: Find 1/2 – 2/5
Since the denominator are different are different, and they cannot divide each other completely, then multiply them.
1/2 – 2/5
5 – 4 /10 = 1/10
Quiz
- Sanchez spent 3/5 of an hour on a jigsaw puzzle. Conrad spent 1/5 of an hour on the puzzle. How much time did they spend working on the puzzle in all?
- Morris jogged 5/8 of a mile on Monday and 3/8 of a mile on Tuesday. How much farther did she jog on Monday?
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