The understanding centers on combining whole-number quantities by coordinating corresponding place-value units: ones with ones, tens with tens, and so on. When a column totals ten or more, the learner composes a unit of the next place and records the remainder, preserving the value of the sum; expanded form, place-value charts, and estimation support interpretation and error checking alongside the standard algorithm. The scope is multi-digit whole numbers, including numbers through commonly used large place values, not decimals, signed numbers, or abstract generalizations.
Line up the numbers by place value: ones under ones, tens under tens, hundreds under hundreds, and so on. Then add from right to left. If a column totals or more, regroup: write the ones digit and carry the extra ten to the next column.
Example:
Ones: . Write in the ones place and carry ten.
Tens: . Write in the tens place and carry hundred.
Hundreds: . Write in the hundreds place and carry thousand.
Thousands: . Write in the thousands place and carry ten-thousand.
Ten-thousands: . Write .
So,
Therefore, .
To check, round the numbers:
Since , the exact answer is reasonable.
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