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To do well in school you'll need to master addition and subtraction with decimals.

Addition and Subtraction 3 (Difficult)

This 11 Plus Maths quiz puts your problem-solving to the test. Use what you know about addition and subtraction to crack each challenge quickly and accurately.

Explore the Topic →

(quiz starts below)

Fascinating Fact:

Add the number of bones in a human (206) and a shark (about zero, because sharks have cartilage) and you still get 206 — sharks bend the rules!

In 11 Plus Maths, practising harder sums improves fluency and understanding of number patterns. Confident subtraction and addition skills form the base for fractions, percentages, and algebra.

Key Terms

Sum: The result you get when numbers are added together.
Difference: The answer you find when one number is subtracted from another.
Equation: A statement showing that two mathematical expressions are equal.

Learn what’s included in the 11 Plus exams with our Guide to 11 Plus Subjects for Parents .

Frequently Asked Questions (Click to see answers)

What kind of maths is in the 11 Plus?

The 11 Plus often includes arithmetic, reasoning, and problem-solving questions that test number skills, logic, and understanding of patterns.

Why is subtraction trickier than addition?

Subtraction requires more careful borrowing and place value awareness, especially when dealing with larger or multi-step problems.

How can I get faster at mental maths?

Practise breaking numbers into parts and spotting patterns. Regular short sessions are better than one long study session.

Try These Related Quizzes

1 .

436.2 - 128.4 = ?

307.8

308.2

308.8

309.2

436.2 - 128.4 = (400 - 100) + (30 - 20) + (6 - 8) + (0.2 - 0.4) = 300 + 10 + -2 + -0.2 = 310 - 2 - 0.2 = 307.8
You can treat this as a normal subtraction. Just make sure you put the decimal point in the right place. Making an estimate (the answer should be somewhere around 300) will help you avoid answers like 30.78 or 3.078!

2 .

16.3 - 2.4 - 16.3 + 29.1 = ?

25.5

26.7

27.6

28.3

TIP: don't waste time writing numbers that cancel each other out, e.g. 16.3 - 16.3 = 0

3 .

19.8 - 21.6 + 239.4 = ?

236.7

267.3

237.6

263.7

Splitting this into hundreds, tens, ones and decimal will help.
19.8 - 21.6 + 239.4 = (200) + (10 + 30 - 20) + (9 + 9 - 1) + (0.8 + 0.4 - 0.6) = 200 + 20 + 17 + 0.6 = 237.6

4 .

392.7 + 63.2 + 7.4 = ?

462.2

462.3

463.2

463.3

Hundreds first, then tens, ones and, finally, decimals:
392.7 + 63.2 + 7.4 = (300) + (90 + 60) + (2 + 3 + 7) + (0.7 + 0.2 + 0.4) = 300 + 150 + 12 + 1.3 = 463.3

5 .

185.9 + 318.6 - 41.7 = ?

462.8

452.8

472.8

442.8

Hundreds, tens, ones then decimals:
185.9 + 318.6 - 41.7 = (100 + 300) + (80 + 10 - 40) + (5 + 8 - 1) + (0.9 + 0.6 - 0.7) = 400 + 50 + 12 + 0.8 = 462.8

6 .

15.3 - 97.9 + 228.2 = ?

146.5

145.6

154.6

164.5

To avoid negative numbers, you can rearrange the problem:
15.3 - 97.9 + 228.2 = 228.2 + 15.3 - 97.9 = 243.5 - 97.9 = 145.6

7 .

82.7 + 27.3 + 309.2 = ?

417.2

418.7

419.2

420.7

Keep an eye out for decimals that add up to whole numbers: 82.7 + 27.3 is the same as 82 + 27 + 1

8 .

325.8 + 18.1 + 900 = ?

1,342.9

1,324.9

1,234.9

1,243.9

You could tackle this problem starting with the highest number: 325.8 + 18.1 + 900 = (900 + 325.8) + 18.1 = 1,225.8 + 18.1 = 1,243.9

9 .

0.9 + 0.3 + 1.8 = ?

2.9

3.1

3.2

9 + 3 + 18 = 30, so 0.9 + 0.3 + 1.8 = 3.0
Also, 0.9 + 0.2 = 1.2, then you can easily spot that 1.8 + 1.2 = 3.0

10 .

728.6 + 60.4 - 235.4 + 100 = ?

652.6

653.2

653.6

654.2

Breaking the problem into hundreds, tens, ones and decimals helps:
728.6 + 60.4 - 235.4 + 100 = (700 + 100 - 200) + (20 + 60 - 30) + (8 - 5) + (0.6 + 0.4 - 0.4) = 600 + 50 + 3 + 0.6 = 653.6

Author: Frank Evans (Specialist 11 Plus Teacher and Tutor)