L1 · The equal sign: two expressions with the same value

Learning goal

“I can work out the value of both sides of an equation, and I can tell if the two sides are really equal. I know the equal sign means 'the same value as' - it does not mean 'write the answer next'.”

Expression — numbers joined by one operation, like 5 + 3 or 4 x 2. An expression has no equal sign.

Value — the amount an expression works out to. The value of 5 + 3 is 8.

Equal — the same amount. Two expressions are equal if their values are the same number.

Equation — a statement with an equal sign that says two expressions have the same value, like 5 + 3 = 6 + 2.

Worked example

Is 6 + 4 = 5 + 5 a true equation? Step 1: Work out the LEFT side on its own: 6 + 4 = 10. Step 2: Work out the RIGHT side on its own: 5 + 5 = 10. Step 3: Compare the two values: 10 and 10 are the same number, so the equation is true. The balance sits level. Say it plainly: the equal sign is a claim - 'these two sides are worth the same.' Your job is to check the claim by valuing each side separately.

Check yourself — explain it

Sam says the equal sign means 'now write the answer.' Why is that not right?

Paired problem — example still visible

Is 9 + 3 = 6 + 6 true? Work out both sides -> Left 12, right 12 - true

Faded completion — last step is yours

"15 - 5 = 4 + □: the left side is worth 10, so the right side must also be worth 10: 4 + ___ = 10" -> 6

Ready to practise?

10 scored questions with a 3-rung hint ladder. Mastery needs 8/10 plus both gate questions.

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