Maryland Math 3.NOS.A.1.c
The Standard
- 3.NOS.A.1
- Apply and extend place value understanding to whole numbers within 10,000.
Estimate quantities by reasoning about their location on a number line, their relationship to benchmark numbers, and rounding to nearest 10 or 100.
Maryland College and Career Ready Standards for Mathematics (2025) · UNDERSTAND PLACE VALUE.
Teacher's field guide
What This Standard Means
What Students Need to Do
- Students locate a number on a number line and judge which nearby ten or hundred it is closest to. They round counts to the nearest 10 or 100 and explain their choice.
What Mastery Looks Like
- Given a count of 347, a student marks it just below 350 on a number line from 300 to 400. They estimate 350 to the nearest ten and 300 to the nearest hundred, and explain why.
Common Misconceptions
- Students may round 347 to 400 because they check the ones digit instead of the tens digit. They may place 347 at 340 on a number line because they ignore the ones digit.
How to Assess It
- Exit ticket: Mark 347 on a number line labeled 300, 350, and 400, then round it to the nearest 10 and 100 and explain each choice.
Lesson moves
Ways to Teach It
Tape a number line from 300 to 400 on the floor; students place 347 and walk to the nearest ten and hundred.
Ask, "Is 347 closer to 300 or 400? How does your answer change when you round to the nearest ten?"
Play rounding bingo with boards of multiples of 10 and 100; call 347 and ask students to cover its nearest ten or hundred.
Give students a ticket count of 347 for the school play; have them report the attendance to the nearest ten and hundred.
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