Year 3 Teaching Sequence 8 - Finding 1, 10, 100 more/less than three-digit numbers (two days)
Prerequisites:
 Count on and back in ones from three digit numbers (see oral and mental starter bank 8)
 Understand place value of three-digit numbers (see teaching sequence 1 and oral and mental starter bank 8)
Overview of progression:
Children add 1, 10 and 100 to three-digit numbers (including numbers such as 399) using place value cards to help, noting
which card needs changing. They move on to subtract 1, 10 and 100 from three-digit numbers, including numbers such as
500.
Note that children may find adding 10 to numbers such as 396 more difficult. The same difficulty may apply to subtracting
10 from 406. Bridging a multiple of 100 always makes a calculation harder, irrespective of the size of the numbers. Thus
593 + 10 is much more difficult than 923 + 10.
Watch out for children who do not understand the value of each digit in three-digit numbers. At this stage, understanding
that in 222 the first ‘2’ has a different value from the second ‘2’ is crucial.
© Original teaching sequence copyright Hamilton Trust, who give permission for it to be adapted as wished by individual users.
Y3 Maths TS8 – Aut – 2days
Objectives:
 Find 1, 10, 100 more/less than three-digit numbers
Whole class
Group activities
Paired/indiv practice
Resources
Make 246 with your place value cards. What is
the number that is one more than 246? Change
your number to 247. Which card do you need
to change?
What is 47 add 10? So what do you think 247
add 10 is? Which card do you need to change?
What is 200 add 100? So what do you think
257 add 100 is? Which card do you need to
change?
Show me 555. What is 1 more than this
number? And 10 more? 100 more?
Practise adding 1, 10 and 100 to other threedigit numbers using place value cards. Include
finding one more than numbers such as 399.
Make slidy box cards with number sentences
adding 1, 10 or 100 to three-digit numbers.
Cover the 1, 10 or 100 with the box.
Group of 4-5 children
Ask chn to enter the number 537 into a
calculator. I want to change the 3 to a
4. What can we do? Add 1? Why not?
What would happen then? Chn try out
their own ideas.
Now we want to change the 5 to a 6.
What should we do? And now we change
the 7 to an 8. How much have we added
on altogether?
Repeat increasing a digit at a time by
one in different three-digit numbers.
Press AC and enter 499. I want to
change all three digits just by adding
one number, what could I do? Would all
the digits change if we added 100? 1?
Let’s try 10! What happens?
Easier: Ask chn to enter 537 + 1. What
happens? Add 10, then 100 discussing
what happens. Repeat with other threedigit numbers, encouraging chn to
predict what will happen.
Group of 4-5 children
Ask chn to enter the number 537 into a
calculator. I want to change the 3 to a
Chn work in pairs to roll three 110 dice to make a three-digit
number less than 900. (If they
roll 10, they roll again.) They add
1, then 10 and then 100 to it.
They record the three associated
number sentences e.g.
357 + 1 = 358
357 + 10 = 367
357 + 100 = 457
Easier: Chn shuffle place value
100s, 10s and 1s cards and take
one from each pile to make a
three-digit number.
Harder: Some chn may feel ready
to add 2, 20 and 200.
 Place value
cards
 Slidy box cards
as opposite
 Calculators
 1-10 dice
Chn work in pairs to roll three 110 dice to make a three-digit
number. (If they roll 10, they roll
 Place value
cards
 Slidy box cards
364 + -
= 374
What number has been added? How do you
know? Which digit has changed?
Make 246 with your place value cards. What is
the number that is one less than 246? Change
your number to 245. Which card do you need
© Original teaching sequence copyright Hamilton Trust, who give permission for it to be adapted as wished by individual users.
Y3 Maths TS8 – Aut – 2days
to change?
What is 45 subtract 10? So what do you think
245 subtract 10 is? Which card do you need to
change?
What is 200 subtract 100? So what do you
think 235 subtract 100 is? Which card do you
need to change?
Show me 555. What is 1 less than this
number? And 10 less? 100 less?
Practise subtracting 1, 10 and 100 from other
three-digit numbers using place value cards.
Include finding one less than numbers such as
400.
Make slidy box cards with number sentences
subtracting 1, 10 or 100 from three-digit
numbers. Cover the 1, 10 or 100 with the box.
364 - -
= 264
What number has been subtracted? How do
you know? Which digit has changed?
2. What can we do? Subtract 1? Why
not? What would happen then? Chn try
out their own ideas.
Now we want to change the 5 to a 4.
What should we do? And now we change
the 7 to a 6. How much have we
subtracted altogether?
Repeat decreasing a digit at a time by
one in different three-digit numbers.
Press AC and enter 700. I want to
change all three digits just by
subtracting one number, what could I
do? Would all the digits change if we
subtracted 100? 1? Let’s try 10! What
happens?
Easier: Ask chn to enter 537 - 1. What
happens? Subtract 10, then 100
discussing what happens. Repeat with
other three-digit numbers, encouraging
chn to predict what will happen.
again.) They subtract 1, then 10
and then 100 from it. They record
the three associated number
sentences e.g.
357 - 1 = 356
357 - 10 = 347
357 - 100 = 257
Easier: Chn shuffle place value
100s, 10s and 1s cards and take
one from each pile to make a
three-digit number.
Harder: Some chn may feel ready
to subtract 2, 20 and 200.
© Original teaching sequence copyright Hamilton Trust, who give permission for it to be adapted as wished by individual users.
as opposite
 Calculators
 1-10 dice
Y3 Maths TS8 – Aut – 2days