Texas Math Models

Try “number line” or “4.5D”

Round both, then compute

4,367 + 2,258 = 6,625 Grade 4

round to the hundred, then do the easy problem 4,3672,258 →→ 4,4002,300 + 6,700 round to the thousand instead and you get 4,000 + 2,000 = 6,000: a wider net 4,367 + 2,258 ≈ 6,700

How this one works

How

round both numbers, then add the easy ones.

Best when

you want a quick check before you solve.

The same problem, other ways