20121031 fractions-pizza-slices-and-adding
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Fractions presentation
Equivalent fractions
Mixed numbers top heavy fractions
Adding fractions
Multiplying fractions
Recap: LCM and HCF
What is LCM of 6 and 9?
What is HCF of 15 and 20?
What is LCM of 2 and 3?
What is HCF of 12 and 8?
What number can 6 and 5 both go into?
Recap: LCM and HCF
What is LCM of 6 and 9? 18
What is HCF of 15 and 20? 5
What is LCM of 2 and 3? 6
What is HCF of 12 and 8? 4
What number can 6 and 5 both go into? 30
Equivalent fractions
In symbols?
=
=
?
In symbols?
=
?
In symbols?
Equivalent fractions quiz
5
4
=
15
12
8
=
3
Equivalent fractions ans
5
4
=
15
12
8
=
3
12
2
Equivalent fractions summary
Mixed & top heavy
Mixed & top heavy
2
5
=
3
2
1
3
?
=
?
?
3
Mixed -> top heavy
1. Multiply whole by bottom
2. Add top
3. Put over bottom
5
4
3
Top heavy -> Mixed
1. Divide top by bottom
2. Answer is whole number
3. Remainder is top
4. Bottom stays same
6
23
Mixed -> top heavy
1. Multiply whole by bottom
2. Add top
3. Put over bottom
Top heavy -> Mixed
1. Divide top by bottom
2. Answer is whole number
3. Remainder is top
4. Bottom stays same
Mixed / top heavy quiz...
7
4
1
3
7
1
3
14
5
17
=
=
=
=
Mixed / top heavy quiz...
7
4
1
3
7
1
3
14
5
17
=
=
=
=
4
29
7
22
4
3
2
3
5
2
Adding fractions
+
=
+
In symbols?
+
=
+
In symbols?
Rule 1: you can only add the tops when the bottoms are the same....
+
=
+
=
Rule 2 different bottoms:
change one or both fractions for equivalent fractions where the
bottoms are the same...
...then add tops
+
=
+
=
+
=
3
1
+
5
4
=
15
5
+
15
12
=
Adding fractions quiz
2
1
+
3
1
=
3
2
+
6
1
=
Adding fractions ans
2
1
+
3
1
=
3
2
+
6
1
=
6
5
6
5
Multiplying fractions
3
1
4
1
4
1
=
12
1
3
1
3
2
4
3
1: multiply tops to get new top
2: multiply bottoms to get new bottom
3: cancel down as needed...
0: write mixed numbers as top heavy
Multiplying fractions quiz
3
2
4
1
=
12
5
3
4
3
=
5
3
4
3
=
2
1
3
2
=
2
workshop
Must: frac-pack
Should: exam questions
Could: stuff on algebraic fractions