Decimal Word Problems

Read the final question first, then identify the quantity it asks you to find. A problem about notebooks might ask for the total price, the change from a payment, or the cost of one notebook. The same numbers could appear in all three situations. Naming the unknown quantity helps you choose a calculation based on the relationship rather than on a familiar word.

List the relevant numbers with their units. Distinguish a price for one item from a total price, and a length from an area. If a runner covers 3.75 km in the morning and 2.6 km in the evening, both distances use the same unit and can be added directly. If quantities use different units, convert them to compatible units before combining them.

Describe the relationship in a short equation. Equal groups often lead to multiplication: four notebooks at €2.75 each cost 4 × €2.75. Sharing a total among equal groups leads to division. Combining distances calls for addition, while finding what remains calls for subtraction. These descriptions explain why the operation fits; an isolated keyword such as “more” cannot decide every problem.

For a problem with several steps, calculate one quantity at a time and label the intermediate answers. Keep exact decimal values until the problem explicitly requests rounding. A perimeter calculation may require adding length and width before doubling their sum. Area instead requires multiplying two lengths, and its unit is squared. Writing each stage separately makes it easier to find where an error occurred.

Finish with a reasonableness check. Estimate with nearby whole numbers, reverse the final operation where possible, and confirm the unit. Four notebooks costing about €3 each should total about €12, so €11 is plausible while €1.10 is not. A total distance must include both journeys. Submit the numerical answer using the unit displayed by the practice tool, and check that it matches the quantity the question requested.