Add whole hundreds (3 addends)

It extends the same logic used for adding single digits to the hundreds place, reinforcing that place value rules are consistent across all digit positions.

Students can simplify by dividing each addend by 100, adding the resulting single digits, then multiplying the sum by 100 — a self-checking strategy that also reinforces multiplication by 100.

Students sometimes forget that the tens and ones places stay zero, writing incorrect digits there — reminding them that only the hundreds column changes helps prevent this error.