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H.1 Write numerical expressions using one operation

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What are numerical expressions?

Numerical expressions are math phrases that use numbers and operation symbols (like +, −, ×, ÷) but do not include an equal sign (=). They show a calculation to be performed, not a completed statement.

Examples:
  • 8 + 4
  • 15 − 7
  • 9 × 3
Note

Think of a numerical expression as a way to represent a situation using numbers and one operation, but without solving it yet.

How to write a numerical expression for a situation

To write a numerical expression, read the situation carefully and decide which operation describes what is happening. Then write the numbers and the correct operation symbol to represent it.

Steps:
  • Read the situation: “Maria bought 6 apples, and each costs $2.”
  • Identify the operation: repeated addition means multiplication.
  • Write the expression: 6 × 2
Note

Each word problem tells a story about a math operation. Words like “total” or “in all” suggest addition, while “each” or “per” often suggest multiplication.

Common clue words for one-operation expressions

Recognizing clue words helps you choose the correct operation when writing a numerical expression from a situation.

Clue Words by Operation:
  • Addition: total, sum, in all, altogether
  • Subtraction: difference, fewer, how many more, left
  • Multiplication: product, times, each, every
  • Division: shared equally, per, out of, divided by
Note

Clue words guide you, but always make sure the expression matches what the situation describes.

Examples of writing expressions for one operation

Here are some examples showing how to translate real-world situations into numerical expressions using one operation.

Examples:
  • “There are 8 boxes with 5 pencils in each box.” → 8 × 5
  • “Liam spent $25 and then spent $10 more.” → 25 + 10
  • “A rope 12 feet long is cut into 3 equal pieces.” → 12 ÷ 3
  • “Sarah had 20 stickers and gave away 6.” → 20 − 6
Note

Each expression shows one operation that represents the situation without solving it. Writing the correct expression is the first step before finding the answer.

Checking your expression

After writing an expression, reread the situation to be sure your operation and numbers match what is described.

Example Check:
  • Situation: “Each of the 4 students has 3 notebooks.”
  • Your expression: 4 × 3
  • Check: Does it show 4 groups of 3? Yes!
Note

Always double-check if your expression makes sense for the situation. Visualizing or drawing a quick picture can help.