Testinar Grade 3 math

Unknown Number in Equations

Students will determine an unknown whole number in multiplication and division equations.

CH01-04 Operations and Algebraic Thinking

Directions Solve each problem. Show your reasoning on the page or on separate paper. Check the answer key only after finishing.

What number makes the equation true? \(\)\square\times7=42\(\)
1. \(8\)
2. \(7\)
3. \(5\)
4. \(6\)
What number makes the equation true? \(\)\square\times5=35\(\)
1. \(9\)
2. \(8\)
3. \(6\)
4. \(7\)
What number makes the equation true? \(\)9\times\square=54\(\)
1. \(8\)
2. \(5\)
3. \(7\)
4. \(6\)
What number makes the equation true? \(\)8\times\square=32\(\)
1. \(4\)
2. \(5\)
3. \(6\)
4. \(3\)
What number makes the equation true? \(\)\square\times6=48\(\)
1. \(10\)
2. \(9\)
3. \(7\)
4. \(8\)
What number makes the equation true? \(\)20\div4=\square\(\)
1. \(4\)
2. \(7\)
3. \(6\)
4. \(5\)
What number makes the equation true? \(\)24\div3=\square\(\)
1. \(9\)
2. \(7\)
3. \(6\)
4. \(8\)
What number makes the equation true? \(\)\square\div4=6\(\)
1. \(10\)
2. \(18\)
3. \(28\)
4. \(24\)

Teacher and parent reference

Answer key and explanations

D. \(6\)
Think: \(42\div7=6\), so the unknown is \(6\). Check: \(6\times7=42\).
D. \(7\)
Use the inverse: \(35\div5=7\). Check: \(7\times5=35\).
D. \(6\)
Divide: \(54\div9=6\). Check: \(9\times6=54\).
A. \(4\)
Think: \(32\div8=4\). Check: \(8\times4=32\).
D. \(8\)
Divide: \(48\div6=8\). Check: \(8\times6=48\).
D. \(5\)
Think: \(5\times4=20\), so \(20\div4=5\).
D. \(8\)
Use the inverse: \(8\times3=24\), so \(24\div3=8\).
D. \(24\)
Use the inverse: \(6\times4=24\), so \(24\div4=6\). Check: \(24\div 4=6\).