Video: Adding Three-Digit Numbers to Two-Digit Numbers by Counting in Tens

Count in tens to find the sum. 643 + 40 = _.

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Video Transcript

Count in tens to find the sum.

643 plus 40 equals what? We have to start at 643 and count forward 40 or four 10s. 643, 653, 663, 673, 683. 643 plus 40 equals 683. We started at 643 on the number line, and we counted forward in tens. 653, 663, 673, 683. 643 plus 40 equals 683.

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