kungfu math p4 slide9 (subtraction fraction)pdf

• subtraction of ∗ like fractions

∗ related fractions

• (Denominators of given fractions should not exceed 12)

What will we learn today?

Fraction Subtraction

In the previous lectures, we have learnt about

Mixed Numbers and

Improper Fractions

Let’s recap!

3 simple steps to add fractions:

• Step 1 – Make sure the bottom numbers

(denominators) are the same

• Step 2 – Add the top numbers (numerators), put the

answer over the denominator.

• Step 3 – Simplify the fraction (if necessary).

For example

Simplify the fraction (if necessary).

Add the top numbers (numerators), put the answer over the denominator.

Try this out!

1. Find the value of . 29

7 + 2

7

Solution

1. Find the value of . 29

7 + 2

7

29

7 + 2

7 =

Step 1 Make sure the bottom numbers (denominators) are the same

Solution

1. Find the value of . 29

7 + 2

7

29

7 + 2

7

29+2

7 =

31

7 =

Step 2 Add the top numbers (numerators), put the answer over the denominator.

Solution

1. Find the value of . 29

7 + 2

7

29

7 + 2

7

29+2

7 =

31

7 = Step 3

Simplify the fraction (if necessary).

= 3

7 4

Applying what we have learnt

3 simple steps to subtract fractions:

• Step 1 – Make sure the bottom numbers

(denominators) are the same

• Step 2 – Subtract the top numbers (numerators),

put the answer over the denominator.

• Step 3 – Simplify the fraction (if necessary).

Try this out!

1. Find the value of . 29

7 - 2

7

Solution

1. Find the value of . 29

7 - 2

7

29

7 - 2

7 =

Step 1 Make sure the bottom numbers (denominators) are the same

Solution

1. Find the value of . 29

7 - 2

7

29

7 - 2

7

29-2

7 =

27

7 =

Step 2 Subtract the top numbers (numerators), put the answer over the denominator.

Solution

1. Find the value of . 29

7 - 2

7

29

7 - 2

7

29-2

7 =

27

7 = Step 3

Simplify the fraction (if necessary).

= 6

7 3

Try this out!

2. Find the value of 1

9 -

2

3 1 -

Try this out!

2. Find the value of 1

9 -

2

3 1 -

Step 1 Make sure the bottom numbers (denominators) are the same

1

9 -

2

3 1 - 1

9 -

2

3 - =

x 3

x 3

9

9

Try this out!

2. Find the value of 1

9 -

2

3 1 -

Step 1 Make sure the bottom numbers (denominators) are the same

1

9 -

2

3 1 - 1

9 -

6

9 - =

9

9

Try this out!

2. Find the value of 1

9 -

2

3 1 - 1

9 -

2

3 1 - 1

9 -

6

9 - =

9

9

9-1-6

9 =

Step 2 Subtract the top numbers (numerators), put the answer over the denominator.

Try this out!

2. Find the value of 1

9 -

2

3 1 - 1

9 -

2

3 1 - 1

9 -

6

9 - =

9

9

9-1-6

9 =

2

9 =

Step 3 Simplify the fraction (if necessary).

Summary

• Step 1 – Make sure the bottom numbers

(denominators) are the same

• Step 2 – Subtract the top numbers (numerators),

put the answer over the denominator.

• Step 3 – Simplify the fraction (if necessary).

Are you ready to try out the questions?

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