Algebra problems with unknowns 11 plus
21 October 2026
Understanding algebraic expressions and unknowns
Algebraic expressions use letters or symbols to stand for unknown numbers. In 11+ maths, these letters are often called unknowns. For example, in the equation x + 5 = 12, x is the unknown.
Why practising algebra matters for 11+
Algebra problems with unknowns appear in many 11+ exams. Practising these skills helps children develop logical thinking and prepares them for harder maths later on.
Worked example
Solve the equation: 3y - 4 = 11
First, add 4 to both sides to move the -4:
3y - 4 + 4 = 11 + 4
This gives 3y = 15.
Next, divide both sides by 3 to find y:
3y ÷ 3 = 15 ÷ 3
So y = 5.
The correct answer is 5.
Key insight: Step-by-step is best
Encourage your child to solve one part of the equation at a time. Always check the answer by putting it back into the original equation to make sure it works.
Tips for supporting your child
Ask your child to explain each step out loud. Use simple numbers and build up slowly. Remind them that making mistakes is part of learning. Practise a variety of problems so they build confidence.
