Operations and Algebraic Thinking: Writing and Interpreting Numerical Expressions (CCSS.5.OA.2)
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Common Core 5th Grade Math › Operations and Algebraic Thinking: Writing and Interpreting Numerical Expressions (CCSS.5.OA.2)
Write an expression that means: Add 6 and 9, then multiply by 4.
$(6+9)\times 4$
$6+(9\times 4)$
$(6\times 9)+4$
$6+9\times 4$
Explanation
The sum of 6 and 9 is $(6+9)$. "Then multiply by 4" means multiply that sum by 4: $(6+9)\times 4$. The others change the order or the operations.
Write an expression that means: Subtract 7 from 20, then divide by 3.
$20\div(7-3)$
$7-(20\div 3)$
$(20-7)\div 3$
$20\div 7-3$
Explanation
Subtract 7 from 20 is $20-7$. "Then divide by 3" means divide that difference by 3: $(20-7)\div 3$. The other choices reverse operations or misplace parentheses.
Which words match the expression $2\times(5+3)$?
Add 2 and 5, then multiply by 3.
Multiply 2 by the sum of 5 and 3.
Add 2, 5, and 3.
Multiply 2 and 5, then add 3.
Explanation
Parentheses show the sum comes first: $(5+3)$. Then multiply that sum by 2: $2\times(5+3)$.
Without calculating, which statement correctly describes $3\times(18,932+921)$?
Add 3 to 18,932 and 921.
Multiply 3 and 18,932, then add 921.
Three more than the sum of 18,932 and 921.
Three times as large as the sum of 18,932 and 921.
Explanation
$3\times(18,932+921)$ means "three times" the sum of 18,932 and 921; the parentheses show the sum is found first.