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How to help your child with algebra: letters, expressions and equations

When letters appear in maths, the difficulty is often about meaning before it is about calculation. A child may read 3x as “thirty-something”, treat the equals sign as “write the answer”, or apply a rule without keeping an equation balanced.

Separate three ideas—what a letter means, how an expression is evaluated, and how an equation is solved—before adding more difficult steps.

By BananaLearn · 3 worked examples · 8 practice questions

Subtracting four from both sides of x + 4 = 11 preserves equality and leaves x = 7.

Start with the meaning

Begin with addition, subtraction, multiplication and division of small whole numbers. Use positive values first. The examples here introduce notation; they do not cover the whole algebra curriculum.

Subtracting four from both sides of x + 4 = 11 preserves equality and leaves x = 7.
Subtracting four from both sides of x + 4 = 11 preserves equality and leaves x = 7.

Explain what the letter is doing

In x + 4 = 11, x represents a number that makes the statement true. In the expression n + 4, n can take different values and the expression changes with it.

A letter is not automatically a hidden answer in every context. Start with a missing-number box, then replace the box with a letter while keeping the same quantities.

Read notation out loud

3x means three times x. If x = 5, then 3x = 15. It does not mean 35, and it does not mean 3 + x. Write the multiplication sign explicitly until the shorthand is familiar.

By contrast, the two-digit numeral 35 means three tens and five ones. Comparing these two kinds of notation helps explain why joining a digit and a letter has a different meaning.

Separate expressions from equations

An expression such as 2x + 3 names a quantity. You can evaluate it when x is given. An equation such as 2x + 3 = 13 states that two quantities are equal; solving asks which value makes that true.

Ask your child what the question requires before calculating. “Evaluate when x = 4” and “solve for x” are not interchangeable instructions.

Keep equality visible

Use a balance drawing for x + 4 = 11. Remove four units from both sides to leave x = 7. Write the same operation beneath each side.

Then substitute seven into the original: 7 + 4 = 11. This independent check catches an operation performed on only one side. Avoid beginning with “move it across and change the sign” before equality makes sense.

Worked examples, step by step

Example 1: Evaluate 4n when n = 6

  1. 4n means 4 × n.
  2. Replace n with six: 4 × 6 = 24.
  3. The answer is 24, not 46 or 10.

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Example 2: Solve x + 8 = 19

  1. Subtract eight from both sides.
  2. x = 19 − 8 = 11.
  3. Check in the original equation: 11 + 8 = 19.

Example 3: Evaluate 2x + 3 when x = 4

  1. Replace x with four: 2 × 4 + 3.
  2. Do the multiplication first: 8 + 3 = 11.
  3. This evaluates an expression; there was no equation to solve.

Common mistakes and useful repairs

Changing the value of the letter within one expression

In x + x, both occurrences of x represent the same value in that expression. If x = 6, the result is 12.

Treating equals as a one-way instruction

Show 8 = 3 + 5 as well as 3 + 5 = 8. Both state equality. This supports equations with the unknown on either side.

Try before revealing

Quick understanding check

1. What does 6x mean?
2. Which value solves x + 5 = 12?

Read the check answers

6 × x. A number written next to a letter represents multiplication.

7. Subtract five from both sides; 7 + 5 = 12.

How to help your child with algebra: letters, expressions and equations — practice sheet

  1. Evaluate 5a when a = 3.

    Show answer and reasoning

    15. 5 × 3 = 15.

  2. Evaluate b + 7 when b = 9.

    Show answer and reasoning

    16. Substitute nine, then add seven.

  3. Solve y + 6 = 14 and check.

    Show answer and reasoning

    y = 8. Subtract six from both sides; 8 + 6 = 14.

  4. Solve 4m = 28.

    Show answer and reasoning

    m = 7. Divide both sides by four; 4 × 7 = 28.

  5. Is 3p + 2 an expression or an equation?

    Show answer and reasoning

    Expression. It has no equality statement. It can be evaluated if p is supplied.

  6. Explain why x = 5 does not solve x + 4 = 12.

    Show answer and reasoning

    5 + 4 = 9, not 12. Substituting into the original tests the proposed value. The solution is x = 8.

Choose the next practice step

Use the questions in this guide to practise this specific skill. If you need another explanation, return to One-step equations: keep both sides equal before trying a fresh problem.

Explore BananaLearn games and the skills they practise →

Help at home: Use a covered quantity

Put a hidden number of counters in a cup and four loose counters beside it. Say the total is eleven. Ask your child to find the cup’s amount, then write x + 4 = 11.

If the objects are easy but the symbols are difficult, keep switching between the drawing, words and equation. If inverse operations are difficult too, practise missing-number arithmetic before longer algebra.

Keep one example of your child’s own working. If the same confusion returns across fresh questions, share that attempt with their teacher and ask which next step fits their current learning.

Questions students and parents ask

Should I teach my own shortcut?

Ask how the teacher represents the method, then use language that preserves equality. A shortcut is useful only when the child can explain why it works and check it.

When is extra help useful?

Bring a specific piece of work if confusion persists across fresh examples. A teacher can distinguish notation, arithmetic and equation reasoning rather than treating all errors as the same problem.

About this resource

BananaLearn created these explanations, diagrams and practice questions. They are not reproduced textbook or past-exam questions. School sequences differ; use the prerequisites to choose a starting point. Read how we prepare learning guides.

Curriculum and teaching references used to check scope:

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