A warm-up worksheet that pairs place value naming with rounding for 3rd grade. A spot-check table asks for the place and value of the bold digit in 472, 815, and 639, eight quick prompts round numbers like 48, 165, 682, and 450, and a Number Detective section ends the page: check every number that rounds to 400 from a list of six, then crack a mystery-number riddle whose answer is 137. The key explains why 450 rounds up and how the riddle narrows to the 130s.
3.NBT.1
“Use place value understanding to round whole numbers to the nearest 10 or 100.”
Parts 2 to 4 all round to tens or hundreds, and the Part 1 spot-check names the very digits (tens and hundreds places) the rounding decisions depend on.
A three-row table lists 472, 815, and 639 with one digit in bold. Students name the place (tens, hundreds, or ones) and its value, such as 70 for the 7 in 472.
Four numbered prompts round 48, 83, 165, and 524, each above its own answer box and preceded by a rounding-rule callout.
Four more prompts (319, 682, 450, and 841) sit beside a signpost illustration. 450 lands exactly on the boundary and must round up to 500.
Question 9 offers six checkboxes (349, 382, 418, 437, 450, 365) for numbers that round to 400. Question 10 is a riddle: rounds to 140 by tens, rounds to 100 by hundreds, odd ones digit greater than 5.
Bell ringer
Project Parts 1 and 2 as students arrive. Seven short answers fit the first five minutes and warm up the exact places the day's rounding lesson uses.
Reasoning finale
Save question 10 for the last five minutes and solve it backwards together: to 140 by tens means 135 to 144, to 100 by hundreds cuts it to the 130s, and the odd digit above 5 forces 137.
Checkbox discussion
In question 9, both 349 and 450 look plausible and both are wrong. Ask students to write one sentence for each rejected number before you reveal the key.
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