CAMBRIDGE PRIMARY MATHEMATICS STAGE 3
END OF UNIT 9: ANSWERS
End of unit 9 test: answers
These tests and mark schemes have been written by the authors. These may not fully
reflect the approach of Cambridge Assessment International Education.
1 3
2 six hundred and three
3 For example: 200 + 150 + 7, 300 + 40 + 17
4 estimate 240 + 80 = 320, 237 + 82 = 319
5 estimate 320 – 60 = 260, 318 – 64 = 254
6 For example: 8 + 3 + 6 = 17, 3 + 8 + 6 = 17, 6 + 3 + 8 = 17, 3 + 6 + 8 = 17
7 estimate 530 – 370 = 160, 529 – 368 = 161
8 a Inverse 419 – 176 = 243 or another fact in the same fact family.
b Inverse 432 + 246 = 678 or another fact in the same fact family.
9
= 73
10 estimate 460 + 270 = 730, 464 + 273 = 737
11 estimate 190 + 260 + 210 = 660, 193 + 264 + 212 = 669
12 16 + 84 = 100 or 84 + 16 = 100 and 27 + 73 = 100 or 73 + 27 = 100
13 a 730
b 310
c 580
14 a 430
b 260
c 550
d 520
If learners struggle with a particular question, compare their answer with
other questions linked to the same or a similar objective to help identify
what is the issue. Then revisit the relevant questions in the Learner’s Book
and Workbook or write some similar questions to target the misunderstanding.
If learners struggle with adding or subtracting 3-digit numbers, work back
through 3-digit numbers add or subtract 2-digit numbers, 3-digit
numbers add or subtract tens to 2-digit numbers add or subtract 2-digit
numbers, with or without regrouping. Find the level at which the learners can
work accurately and gradually work towards adding and subtracting 3-digit
numbers. Unit 9 underpins some of the content of Unit 11 and addition and
subtraction in Stage 4.
Cambridge Primary Mathematics 3 – Moseley & Rees © Cambridge University Press 2021
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CAMBRIDGE PRIMARY MATHEMATICS STAGE 3
Section
9.1
9.1
9.1
9.1
9.1
9.1
9.2
9.2
9.2
9.2
Learning objective
3Nc.02 Count on and count back in steps of
constant size: 1-digit numbers, tens or
hundreds, starting from any number (from
0 to 1000).
3Ni.01 Recite, read and write number
names and whole numbers (from 0 to
1000).
3Ni.02 Understand the commutative and
associative properties of addition and use
these to simplify calculations.
3Ni.04 Estimate and add whole numbers
with up to three digits (regrouping of ones
or tens).
3Np.01 Understand and explain that the
value of each digit is determined by its
position in that number (up to 3-digit
numbers), including zero as a
place holder.
3 Np.03 Compose, decompose and
regroup 3-digit numbers, using hundreds,
tens and ones.
3Nc.02 Count on and count back in steps of
constant size: 1-digit numbers, tens or
hundreds, starting from any number (from
0 to 1000).
3Nc.04 Recognise the use of an object to
represent an unknown quantity in addition
and subtraction calculations.
3Ni.01 Recite, read and write (number
names and) whole numbers (from 0 to
1000).
3Ni.04 Estimate and subtract whole
numbers with up to three digits
(regrouping of ones or tens).
END OF UNIT 9: ANSWERS
Question
4, 5, 10, 11
2, 3, 4, 8, 10, 11
1, 6, 11
4, 7, 10
2, 3, 4, 10
2, 3, 4
5, 7
9
5, 7, 8, 9, 10
5, 7, 8
Cambridge Primary Mathematics 3 – Moseley & Rees © Cambridge University Press 2021
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CAMBRIDGE PRIMARY MATHEMATICS STAGE 3
9.2
9.2
9.3
9.3
9.3
9.3
9.3
9.3
9.3
3Np.01 Understand and explain that the
value of each digit is determined by its
position in that number (up to 3-digit
numbers), including zero as a place holder.
3Np.03 Compose, decompose and regroup
3-digit numbers, using hundreds, tens and
ones.
3Nc.02 Count on and count back in steps of
constant size: 1-digit numbers, tens or
hundreds, starting from any number (from
0 to 1000).
3Ni.01 Recite, read and write number
names and whole numbers (from 0 to
1000).
3Ni.02 Understand the commutative and
associative properties of addition and use
these to simplify calculations.
3 Ni.03 Recognise complements of 100 and
complements of multiples of 10 or 100 up
to 1000.
3Ni.04 Estimate add and subtract whole
numbers with up to three digits
(regrouping of ones or tens).
3Np.01 Understand and explain that the
value of each digit is determined by its
position in that number (up to 3-digit
numbers).
3Np.03 Compose, decompose and regroup
3-digit numbers, using hundreds, tens and
ones.
END OF UNIT 9: ANSWERS
5, 7, 8, 9, 10
5, 7, 8, 9, 10
13
13, 14
12
12, 13
13, 14
12, 13, 14
12, 13, 14
Cambridge Primary Mathematics 3 – Moseley & Rees © Cambridge University Press 2021
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