Download Simm Mult 3 Fractions Session plans

Multiplication 3
Fractions
Objectives

Know all multiplication tables to 12 × 12

Recognise multiples of 2 to 12 to the 11th multiple

Find factors of two-digit numbers

Multiply a fraction by a whole number

Multiply pairs of fractions
For this unit you will need:
12-section counting stick (see resources), playing cards, 0-9 dice,
Multiplying Fractions millionaire at http://www.mathplay.com/Multiplying-Fractions-Millionaire/Multiplying-FractionsMillionaire.html
Watch out for pupils who:

do not know their 6, 7 and 8 times tables. This lack of knowledge
will really slow down their work in multiplication and division so
use day 1’s activities with other tables as necessary;

do not realise that to find half of a fraction for example is the same
as multiplying a fraction by one half.
HSNP © Hamilton 2013
Simmering Term 2
Multiplication 3
Session 1
Objective: Know the 11 and 12 times tables up to the 12th multiple
Teacher input with whole class
 Use the counting stick (see resources) to support chanting of the 11
times table: one 11 is 11, two 11s are 22, three 11s are 33… twelve 11s
are 132. Point out how easy the 11 time table is up to 11 × 11 and 11 ×
12. Remind pupils how they can use partitioning to work this out if they
can’t yet remember these facts, e.g. (10 × 11) + (2 × 11). Point to
various places on the stick and ask pupils to call out the correct
multiples of 11.
 Repeat for the 12 times table, writing the multiples of 12 under the
counting stick to begin with.
Paired pupil work
 Pupils work in pairs to remove the Kings, then shuffle a pack of playing
cards and place in a pile face down. They multiply red numbers by 11
and black numbers by 12. Jokers count as 0, Jacks count as 11, Queens
as 12. They turn over a card and the first to correctly multiply it wins
the card. They carry on until there are no more cards. Who won most
cards?
Teacher input with whole class
 Work together as a class to list the pair of factors of 72.
Paired pupil work
 Pupils work in pairs to investigate which number in the 12 times table
has the most number of factors.
HSNP © Hamilton 2013
Simmering Term 2
Multiplication 3
Session 2
Objective: Multiply pairs of fractions
Teacher input with whole class
 Write 6 x 1/8 = on the board. Discuss how this is asking us to find 6 lots
of one eighth. Imagine a pizza cut into 1/8s. We have six of these slices.
Ask pupils to write the answer. Check that we all agree it is 6/8.
Remind pupils that we can reduce this to its simplest form, ¾.
 Repeat this, asking pupils to multiply 4 x 5/6. They write the answer
(20/6 which can be reduced to 31/3).
 Write ½ of ¾ on the board and ask pupils to discuss in pairs how they
can find half of ¾. Draw out halving each quarter to give an eighth, so
half of ¾ is 3/8. Point out how we have multiplied the denominator by
2. Write ½ x ¾ = 3/8
 Ask pupils to find half of the following fractions: 2/5, ½, 2/3, 5/6.
 Pupils discuss in pairs how they might find 1/3 of ¾ and then 2/3 of ¾.
Draw out dividing each quarter into 3, and so 1/3 of ¾ is 3/12, i.e. we
have multiplied the denominator by 3. So how do we find 2/3? (Multiply
the numerator by 2.) Multiplying pairs of fractions is easier than
adding or subtracting pairs of fractions, as we just multiply the
numerators together the denominators together. Remind pupils how
to do this with several pairs of fractions, e.g. 2/3 × ¾ and 3/10 × 4/5,
reducing the fractions.
Paired pupil work
 Pupils play the following game in pairs. They each roll a dice twice to
make a fraction. They then multiply the fractions together, simplifying
the fraction where they can. How many can they do in three minutes?
Teacher input with whole class
 Ask pupils to find ½ of ¼. What is ½ of the answer? And ½ of that
answer? Keep going!
HSNP © Hamilton 2013
Simmering Term 2
Multiplication 3
Session 3
Objective: Multiply pairs of fractions
Teacher input with whole class
 Write ½ of 4/5 on the board. Point out that ½ of 1/5 is 1/10 so ½ of 3/5 is
3
/10. We have multiplied the denominator by 2. Point out that the
answer is always smaller than either of the fractions being multiplied.
If we have ½ of ¼ of a piece of cake, we have a smaller piece than ½ or
¼.
 Ask pupils to write the product of ¼ and 2/5. Remind pupils that a quick
way to multiply fractions is to multiply the numerators and the
denominators. So the product is 2/20 or 1/10. Again, point out that the
answer is smaller than either of the fractions being multiplied.
 Write 7/8 x 2/5 on the board and ask pupils to write the answer.
Multiplying pairs of fractions is easy! The answer is always smaller
than the fractions being multiplied.
 Together work through the stages in working out 4/5 x 10/11 making sure
that pupils remember how to reduce a fraction to its simplest form.
Repeat to find the product of ½ x ¾ x 2/9 . Again, the answer is smaller
than any of the fractions being multiplied.
Pupil work
 Play Multiplying Fractions millionaire at http://www.mathplay.com/Multiplying-Fractions-Millionaire/Multiplying-FractionsMillionaire.html. Play one half of the class against the other half. Keep
the pace fast and don’t take any prisoners!
Teacher input with whole class
 Ask pupils to find the product of 7/9 x 9/14. Can they see a quick way
of doing this? Point out that we can cancel the 9s.
7x9
= 7 =1
9 x 14
14
2
3
4
Repeat to do /8 x /15.

HSNP © Hamilton 2013
Simmering Term 2