Skill: Add multiples of 100 mentally

Explanation and Free Practice Resources

Adding a multiple of 100 means combining whole hundreds: the hundreds place increases by the corresponding number of hundreds while the tens and ones remain unchanged. For three-digit numbers with results within 1,000, this reasoning supports efficient mental addition and can be represented by jumps of 100 on a number line or by place-value notation; it does not include larger numbers or generalized algorithms beyond this range.

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Detailed Explanation: Add multiples of 100 mentally

To add a multiple of $100$ , add whole hundreds. The tens and ones digits stay the same.

Example:

347+500

Think of $500$ as $5$ hundreds.
Start with $347$ and add $100$ five times:

347\to447\to547\to647\to747\to847

The hundreds digit increased by $5$ , while the $4$ tens and $7$ ones stayed the same.

Therefore,

347+500=\boxed{847}

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Addition - Whole Number - Add Multiple of 100 to a Number

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