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Substituting numbers into an expressionHow to solve an expression through substitution

When you know the value for letters in an algebraic expression you can substitute these values into the expression and solve it.

Part of MathsExpressions and equations

How to solve an expression through substitution

  • Substitution means putting numbers in place of letters to calculate the value of an expression.
  • An expression can be a combination of numbers, letters and operators, grouped together.

Look at the examples below:

Example

If \(a~=~2\) and \(b~=~5\)

Find \(3a~+~2b\)

How to solve the expression:

\(3a~+~2b\)

Substitute \(a\) with the value \(2\) and \(b\) with \(5\)

\({3}\times{2}~+~{2}\times{5}\)

\(=~6~+~10\)

\(=~16\)