CoreIn almost every paper that tests this subjectAbout 60 seconds a question in the test
The big idea
11+ papers expect quick, accurate written methods: column addition and subtraction, long or grid multiplication, and short or long division.
When a calculation mixes operations, follow BIDMAS: Brackets, Indices, Division & Multiplication (left to right), Addition & Subtraction (left to right).
Tips that save marks
Estimate first (round each number) so you can spot silly answers.
Check division by multiplying back.
Know your times tables to 12 × 12 instantly. It saves minutes.
A worked example
Calculate 6 + 4 × 5.
Multiplication comes first: 4 × 5 = 20.
Then add: 6 + 20 = 26.
A common wrong answer is 50 (adding first).
Now try five
Try each one before you look at the answer: answering from memory is what makes it stick. Tap an option to check it. Most children get three or four right at first; five out of five means move on to the next topic.
Question 1Aim for about 60 seconds
What is the missing digit in this subtraction?
9
0
2
6
−
5
6
□
1
3
3
4
5
Show the worked answer
Answer: A, 8
How to work it out
Check with addition: the answer plus the number being taken away gives the top number.
3,345 + 5,681 = 9,026, so the missing digit is 8.
Why the other options are wrong
B (4): This is the digit in the answer, not in the number taken away.
C (9): This exchanges when there is no need.
D (7): One too few: check the exchange again.
E (1): Test this digit: the subtraction would not give the answer shown.
Question 2Aim for about 60 seconds
Calculate 646 × 15.
Show the worked answer
Answer: B, 9690
How to work it out
Long multiplication: 646 × 10 = 6,460 and 646 × 5 = 3,230.
Add them: 9,690.
Question 3Aim for about 60 seconds
Find the missing number that makes both sides equal.
83 + 468 = ? + 461
Show the worked answer
Answer: B, 90
How to work it out
The left side is 83 + 468 = 551.
So ? + 461 = 551, and ? = 551 − 461 = 90.
A quicker way: 461 is 7 less than 468, so ? must be 7 more than 83.
Why the other options are wrong
A (7): This is only the difference between 468 and 461.
C (551): This is the total of the left side. The right side already has 461 in it, so the missing number is smaller.
D (76): The right side's number is 7 smaller, so the missing number must be 7 bigger, not smaller.
E (83): This assumes 468 and 461 are the same; they differ by 7.
Question 4Aim for about 60 seconds
Calculate:
82 − 40 ÷ 5
Show the worked answer
Answer: E, 74
How to work it out
Divide before you subtract (BIDMAS): 40 ÷ 5 = 8.
Then 82 − 8 = 74.
Why the other options are wrong
A (75): A near miss: check the working again.
B (8): This is only 40 ÷ 5; it still has to be taken from 82.
C (90): This adds instead of subtracting.
D (42): This subtracts 40 and forgets to divide it by 5.
Question 5Aim for about 60 seconds
Calculate 41,854 − 8,743.
Show the worked answer
Answer: B, 33111
How to work it out
Line up the columns and subtract, exchanging where needed: 33,111.
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