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Use symbols to represent unknown values

An unknown whole-number quantity in an equation or simple numerical pattern can be represented by a symbol, such as a box or letter, including in forms like □ + 275 = 600, 4 × n = 28, or 56 ÷ □ = 7. The symbol represents a specific value in that relationship, and reasoning about equality, inverse operations, and known number relationships supports finding it; generalized formulas, multiple variables, and non-whole-number equations are beyond this scope.

Detailed Explanation: Use symbols to represent unknown values

A symbol can stand for an unknown number. The symbol might be a box, a letter, or another mark.

Example:

□+275=600\square + 275 = 600

We need to find the number that makes the equation true.

  1. The symbol has 275 added to it. Use the inverse operation, subtraction, to find the unknown:
600−275=325600 - 275 = 325
  1. Replace the symbol with 325325:
325+275=600325 + 275 = 600
  1. Check the answer. Since the equation is true, the unknown value is:
325\boxed{325}

So, in □+275=600\square + 275 = 600, the symbol represents 325325.

Learn by doing: Use symbols to represent unknown values

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