Download KU Mult 4 Decimals by single digit numbers Session plan

Multiplication 4
Decimals by single digit numbers
Objectives

Know the 11 and 12 times tables up to the 12th multiple

Find factors of two-digit numbers

Multiply two-digit numbers with one decimal place by single-digit
numbers, e.g. 3.4 × 6
For this you unit will need:
12-section counting stick (see resources), playing cards, Tables wheel at
http://www.wmnet.org.uk/resources/gordon/Function%20wheel%20v6.s
wf, ITP Number dials at http://www.teachfind.com/nationalstrategies/mathematics-itp-number-dials
Watch out for pupils who:

do not know their 2, 3, 4, 5, 6, 7, 8 and 9 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;

think that 4 × 0.3 = 0.12 for example. Count in steps of 0.3 to help
them to realise that this is not the case.
HSNP © Hamilton 2013
Keeping Up Term 2
Multiplication 4
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 times 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.
 Use the Tables wheel at
http://www.wmnet.org.uk/resources/gordon/Function%20wheel%20v
6.swf, entering 12 into the keypad. Click on the inner numbers and ask
pupils to say each of the outer numbers before you click on them. Point
out that 11 × 12 and 12 × 12 aren’t on this wheel, that we’ve already
learned 11 × 12 as part of the 11 times table so 12 × 12 is the only fact
missing.
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?
HSNP © Hamilton 2013
Keeping Up Term 2
Multiplication 4
Session 2
Objectives: Find factors of two-digit numbers
Teacher input with whole class
 Write the following numbers on the board and ask pupils to discuss
which might be the odd one out: 15, 60, 32, 21. After some discussion
draw out that 32 might be the odd one out as 15, 60 and 21 have 3 as a
factor but 32 does not.
 Repeat with 24, 25, 30 and 42 (24, 30 and 42 have 6 as a factor).
 Write the following numbers and ask pupils to work in pairs to find a
number that is a factor of ALL of them: 24, 27, 36 and 51 (3).
Paired pupil work
 Pupils work in pairs. One writes three numbers which all have one
number as a factor (e.g. choosing three numbers from one times
table). The other player guesses the factor. Are there any other
numbers which are also a factor?
 Repeat so that pupils have three goes each.
Teacher input with whole class
 Write 54 on the board and remind pupils how to find all the pairs of
factors. Begin with asking if 2 is a factor, and if so which number goes
with it to make the pair. List 2, 27. Repeat with 3, 4, 5 (pointing out
that 5 is obviously not a factor as 54 does not end in 0 or 5), 6, 7 and 8.
Do we need to go any further? No, because we already have 9 with 6.
Paired pupil work
 Pupils work in pairs to find all the pairs of factors of 36 and 48.
HSNP © Hamilton 2013
Keeping Up Term 2
Multiplication 4
Session 3
Objective: Multiply two-digit numbers with one decimal place by singledigit numbers, e.g. 3.4 × 6
Teacher input with whole class
Use the ITP Number dials at http://www.teachfind.com/nationalstrategies/mathematics-itp-number-dials, click on the ‘1’ icon several
times and use the toggle to change the central number to 0.7. Together
count on in steps of 0.7 as you click on each outside box. How are these
numbers different to those in the 7 times table? (A tenth of each answer.)
 Repeat for the 0.8 times table, asking pupils to write the answers on
their whiteboards before you click on each box to confirm.
Individual practice
 Pupils write out the 0.9 times table.
Teacher input with whole class
 Remind pupils how they can use the grid method to keep track of the
partitioning when multiplying numbers such as 6 × 3.4.
×
3
0.4
6
18
2.4
20.4
Individual practice
 Pupils estimate, then use the grid method to find the exact answers to
3 × 4.2, 4 × 5.6, 6 × 3.8, and 8 × 3.7.
Teacher input with whole class
 Discuss how the answers to 3 × 4.2 and 3 × 42 are different by a factor
of 10. Suggest that another way of multiplying decimals is to multiply
the decimal by 10, carry out the multiplication and then divide back by
10 at the end. Ask them to do this for two of the multiplications and
check that they get the same answer.
HSNP © Hamilton 2013
Keeping Up Term 2