Mentally Add/Subtract 10 or 100 - 2nd Grade Math
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What is the result of subtracting $100$ from $800$?
What is the result of subtracting $100$ from $800$?
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$700$. Subtracting $100$ decreases the hundreds digit by $1$.
$700$. Subtracting $100$ decreases the hundreds digit by $1$.
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What is the result of subtracting $10$ from $709$?
What is the result of subtracting $10$ from $709$?
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$699$. Subtracting $10$ decreases the tens digit by $1$.
$699$. Subtracting $10$ decreases the tens digit by $1$.
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What is the result of adding $10$ to $709$?
What is the result of adding $10$ to $709$?
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$719$. Adding $10$ increases the tens digit by $1$.
$719$. Adding $10$ increases the tens digit by $1$.
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What is the result of subtracting $100$ from $590$?
What is the result of subtracting $100$ from $590$?
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$490$. Subtracting $100$ decreases the hundreds digit by $1$.
$490$. Subtracting $100$ decreases the hundreds digit by $1$.
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What is the result of adding $10$ to $356$?
What is the result of adding $10$ to $356$?
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$366$. Adding $10$ increases the tens digit by $1$.
$366$. Adding $10$ increases the tens digit by $1$.
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What is the result of adding $10$ to $489$?
What is the result of adding $10$ to $489$?
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$499$. Adding $10$ increases the tens digit by $1$.
$499$. Adding $10$ increases the tens digit by $1$.
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What is the result of adding $100$ to $356$?
What is the result of adding $100$ to $356$?
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$456$. Adding $100$ increases the hundreds digit by $1$.
$456$. Adding $100$ increases the hundreds digit by $1$.
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What is $900 - 100$?
What is $900 - 100$?
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$800$. Subtract $1$ from the hundreds digit: $9 - 1 = 8$.
$800$. Subtract $1$ from the hundreds digit: $9 - 1 = 8$.
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What is $835 + 100$?
What is $835 + 100$?
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$935$. Add $1$ to the hundreds digit: $8 + 1 = 9$.
$935$. Add $1$ to the hundreds digit: $8 + 1 = 9$.
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What happens to the hundreds digit when you add $100$ to a number from $100$ to $900$?
What happens to the hundreds digit when you add $100$ to a number from $100$ to $900$?
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The hundreds digit increases by $1$. Adding $100$ changes only the hundreds place value.
The hundreds digit increases by $1$. Adding $100$ changes only the hundreds place value.
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What happens to the tens digit when you add $10$ to a number from $100$ to $900$?
What happens to the tens digit when you add $10$ to a number from $100$ to $900$?
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The tens digit increases by $1$ (and may cause a carry). Adding $10$ affects the tens place, which may carry to hundreds.
The tens digit increases by $1$ (and may cause a carry). Adding $10$ affects the tens place, which may carry to hundreds.
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What is $615 - 100$?
What is $615 - 100$?
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$515$. Subtract $1$ from the hundreds digit: $6 - 1 = 5$.
$515$. Subtract $1$ from the hundreds digit: $6 - 1 = 5$.
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What is $300 - 100$?
What is $300 - 100$?
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$200$. Subtract $1$ from the hundreds digit: $3 - 1 = 2$.
$200$. Subtract $1$ from the hundreds digit: $3 - 1 = 2$.
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What is $672 - 100$?
What is $672 - 100$?
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$572$. Subtract $1$ from the hundreds digit: $6 - 1 = 5$.
$572$. Subtract $1$ from the hundreds digit: $6 - 1 = 5$.
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What is $508 + 100$?
What is $508 + 100$?
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$608$. Add $1$ to the hundreds digit: $5 + 1 = 6$.
$608$. Add $1$ to the hundreds digit: $5 + 1 = 6$.
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