Year 5 Teaching Sequence Spring 2 – Ordering and rounding decimals (two days)
Prerequisites:
 Understand decimal notation for tenths and hundredths in context e.g. length, converting 125cm to m (see Year 4
spring teaching sequence 1 and oral and mental starter bank 2)
 Recognise the equivalence between tenths written as vulgar fractions (1/10) and decimal fractions (0.1), and between
hundredths written as vulgar and decimal fractions (see Year 5 spring teaching sequence 10 and oral and mental
starter bank 2)
 Round three-digit numbers to the nearest 100 (see oral and mental starter bank 2)
Overview of progression:
Children place numbers with one decimal place on a number line, then do the same for numbers with two decimal places. They
use this experience to order a mixed set of numbers with one or two decimal places. Numbers with one or two decimal
places are rounded to the nearest whole number, and the reasons for doing so discussed.
Note that children should be able to use their knowledge of placing two-digit numbers on a 0-100 line to place decimals with
two places between neighbouring whole numbers.
Watch out for children who think that 1.75 is greater than 1.8 because 75 is more than 8.
Watch out for children who write 0.3 as 0.30 - they correctly see this as equivalent to 30 hundredths but incorrectly add a
zero as we do in money, e.g. £0.30.
© Original teaching sequence copyright Hamilton Trust, who give permission for it to be adapted as wished by individual users.
Y5 Maths TS2 – Spr – 2days
Objectives:
 Order numbers with one and two decimal places and place them on a number line
 Round a number with one or two decimal places to the nearest whole number
Whole class
Group activities
Paired/indiv practice
Resources
Show chn a 100 bead bar and say that one end
represents 0 and the other 1. Each bead
represents one hundredth. How can we write
this? Write 1/100 and 0.01 on the board. What
does each group of ten beads represent? Talk
to your partner. How can we write this? Write
10/100, 1/10 and 0.1 on the board. Ask chn to
come up and hang tags to show 0.1, 0.2, 0.3,
0.5, and 0.9. See how 0.5 comes half way along
the beads. What’s another way to write 0.5?
What number comes half way between 0.2 and
0.3? Write 0.25 on a tag and hang it after the
25th bead. What does the 2 in 0.25 represent?
And the 5? Write down two other numbers
that come between 0.2 and 0.3.
Show a counting stick and say that one end
presents 0 and the other 1. Point to 0.35.
What number goes here? And here? (Pointing
to 0.75, then 0.49 and 0.51). Now say that one
end represents 2 and the other 3. Count from
2 to 3 in steps of 0.1. Point to 2.2 and 2.3.
Write three numbers on your whiteboards
that go between 2.3 and 2.4. Choose three
whiteboards showing different numbers and
ask children to help you to put them in order.
Group of 4-5 children
Sketch a line from 0 to 1 on the
flipchart. Mark but do not label where
0.63 comes to. I’m thinking of a number
on this line. You can suggest a number
and I will tell you whether my number is
more or less than that number. Take
several numbers and say whether the
number you are thinking of is more or
less.
You can now ask me to mark on two
different tenths, e.g. 0.1 and 0.2 to
help you to guess my number. Which
tenths do you think would be useful?
Mark on the tenths they suggest (e.g.
0.6 and 0.7). Children continue to
suggest numbers and you say where the
secret number is more or less until they
guess it.
Repeat.
Easier: Mark on 0.5 to begin with, and
suggest neighbouring tenths if
necessary.
Harder: Ask a pair of children to take
your place in thinking of a number the
second time you play the game.
Ask chn to place numbers with
two decimal places on number
lines, which are ‘empty’ between
neighbouring whole numbers (see
resources). They then order a set
of given decimals.
Easier: Children’s lines have
tenths marked (but not labelled).
 100 bead bar
and wipeon/wipe-off
tags (or pieces
of card and
paperclips)
(perhaps
borrowed from
a year 2 or 3
teacher) or use
ITP Ordering
numbers,
choosing 100
beads
 Counting stick
 Activity sheets
(see resources)
© Original teaching sequence copyright Hamilton Trust, who give permission for it to be adapted as wished by individual users.
Y5 Maths TS2 – Spr – 2days
Show chn a counting stick and say that one end
represents 2 and the other 3. Count from 2 to
3 in steps of 0.1. Point to 2.3. Is 2.3 nearer to
2 or 3? So if we are rounding to the nearest
whole number 2.3 rounds to 2. What other
numbers with one decimal place might round to
2? Point to 2.7. Is 2.7 nearer to 2 or 3? So 2.7
rounds to 3. Write another number with one
decimal place that rounds to 3 on your
whiteboards. Point to 2.5. What about this
number? What multiple of 10 would you round
25 to? 30. So we round 2.5 up to 3.
Point to 2.2 and 2.3. Write a number on your
whiteboards that goes between 2.3 and 2.4.
You've written different numbers but which
whole number is closest to all of them? So
they all round to 2. Think of another number
with two decimal places that will round to 2.
Point to 2.8 and 2.9 and repeat. Which whole
number do all your numbers round to? Write
another number with two decimal places that
will round to 3. Can you think of a number
greater than 3 with two decimal places that
will round down to 3?
Later this term we learn to add numbers with
decimal places, and rounding will help us to
make an estimate. Write 2.23 + 5.89 on the
board. What do you think the answer will be to
the nearest whole number? How did you work
that out? Sometimes we don’t round to the
nearest whole number, but round up. For
Group of 4-5 children
Draw a three by two grid on your
whiteboards, and write six numbers
between 0 and 10 with one decimal
place.
Ring a number if it rounds to 5. Which
numbers have you rung? Which are
rounded down, and which rounded up?
Ring a number if it rounds to 9.
Repeat until a child has rung six
numbers.
Repeat, this time asking children to
write down six numbers between 0 and
10 with two decimal places.
Easier: Children mark their six numbers
on a 0-10 line (see resources) rather
than writing them on a grid.
Chn mark on numbers with one and
two decimal places on blank
number lines and round each to
the nearest whole number (see
resources).
Easier: Children’s number lines
have tenths marked (but not
labelled).
Harder: If children work well, ask
them to choose four numbers with
two decimal places to round to
the nearest tenth.
© Original teaching sequence copyright Hamilton Trust, who give permission for it to be adapted as wished by individual users.
 Counting stick
 0-10 number
line with
tenths marked
 Activity sheets
(see resources)
Y5 Maths TS2 – Spr – 2days
example, If I’m buying material for some new
curtains, and have worked out that I need a
length of 3.2 metres to make my curtains, it
wouldn't be very helpful if I only bought 3
metres of material! My curtains would be too
short! If the shop sold material only by the
metre, I’d have to buy 4 metres and have some
left. Perhaps I could make matching cushion
covers!
© Original teaching sequence copyright Hamilton Trust, who give permission for it to be adapted as wished by individual users.
Y5 Maths TS2 – Spr – 2days