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Mr. Roche: 1st Year maths
1
Fractions, Decimals & Percentages
Mr. Roche: 1st Year maths 2
FractionsMust be able to:
1. Change Mixed Numbers into Improper Fractions
2. Change Improper Fractions into Mixed Numbers
3. Multiply Fractions
4. Divide Fractions
5. Add/Subtract Fractions
3Mr. Roche: 1st Year maths
1. Change Mixed Numbers to Improper Fractions
E.g. Change into an improper fraction.5
23
+
x
=
53(5) = 15
15 + 2 = 17
17
The Denominator
doesn’t change
Mr. Roche: 1st Year maths 4
2. Change Improper Fractions to Mixed Numbers
E.g. Change into a mixed number.4
13
=
4Denominator?
What is the shape of the
answer?
The Denominator
doesn’t change
Now Divide: 13 ÷ 4
13 ÷ 4 = 3 Times
Remainder 1
3Whole
Number?
1Numerator
?
Mr. Roche: 1st Year maths 5
3. Multiply Fractions
6
5
4
3E.g. Multiply
6
5
4
3
Step 1Look for
cancellations
1
2
Step 13 ÷ 3 = 16 ÷ 3 = 2
Step 2Multiply
Top x TopBottom x Bottom
=Step 2Multiply 1 x 5 = 54 x 2 = 8
Mr. Roche: 1st Year maths 6
Step 2Look for
cancellations
3. Divide Fractions
E.g. Divide
5
7
10
3
1
2
Step 1Rewrite:
“Invert and Multiply”
=7
5
10
3
Step 210 ÷ 5 = 25 ÷ 5 = 1
Step 3Multiply
Top x TopBottom x Bottom
Step 3Multiply 3 x 1 = 3
2 x 7 = 14
Mr. Roche: 1st Year maths 7
5. Add/Subtract Fractions
6
5
4
1E.g. Add
Step 1Find the L.C.D.
6
5
4
1
Consider the multiples of the
bigger denominator6
121824
12LCD?
Step 2Divide & Multiply12 ÷ 4 = 3
1 x 3 = 3 +12 ÷ 6 = 2
2 x 5 = 10
Step 3Add or
Subtract
12
13
Mr. Roche: 1st Year maths 8
Mr. Roche: 1st Year maths 9
Mr. Roche: 1st Year maths 10
Mr. Roche: 1st Year maths 11
Mr. Roche: 1st Year maths 12
Mr. Roche: 1st Year maths 13
Mr. Roche: 1st Year maths 14
Mr. Roche: 1st Year maths 15
