Unit 6 · Algebra
Square Symbol — What Number Does It Represent?
Lesson 2 of 24
9 × □ = 108 → □ = 12. Then △ + 12 = 36 → △ = 24. Two steps, each a single equation.
Two-step symbol substitution questions are among the most common easy questions in Selective MR. The first equation gives you one symbol’s value; you plug it into the second equation to find the other.
The examiner checks whether students (1) solve the first equation correctly by division, (2) substitute the result into the second equation, and (3) subtract rather than confusing the two symbols.
Two equations use two different symbols. The first equation can be solved directly; its result is substituted into the second to find the unknown symbol.
Best approach: Solve equation 1 first (divide both sides by 9). Substitute the result into equation 2 and solve by subtraction.
Question
□ always represents the same number.
△ represents a different number.
If
9 × □ = 108
and
△ + □ = 36
What is △?
Select an answer to see the explanation.
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