Ctrl+k

Represent a problem with an equation

An equation represents the quantitative relationships in a problem, using numbers, operation symbols, and a letter or symbol for an unknown; the unknown may be the result, a starting quantity, a change, a group size, or the number of groups. The learner connects addition and subtraction, and multiplication and division, to the situation’s structure rather than choosing an operation from isolated words, and understands that the equals sign asserts that two quantities have the same value.

Detailed Explanation: Represent a problem with an equation

An equation shows how the quantities in a problem are related. First, decide what the unknown represents. Use a letter, such as ss, for that unknown.

Example:
Mia had some stickers. She gave away 77 stickers and now has 1515 stickers. How many stickers did she have at the start?

  1. Name the unknown.
    The starting number of stickers is unknown, so let ss represent it.

  2. Describe what happened.
    Mia started with ss stickers and gave away 77. Giving away means subtracting:

s7s-7
  1. Show what remains.
    She has 1515 stickers now. The expression s7s-7 and the number 1515 have the same value, so use an equals sign:
s7=15s-7=15
  1. Solve and check.
    Add 77 to both sides:
s=22s=22

Check the situation:

227=1522-7=15

Mia had 2222 stickers at the start. The equation matches the story because it shows the starting amount, the change, and the amount left.

Learn by doing: Represent a problem with an equation

Click a topic below to practice the foundational skills you'll need, learn the steps, or master this skill

Practice with unlimited practice problems

Algebra Meals - 3 Meals, 2 Items (Simple Substitution, Compound Answer), to Equation


    ?