Maryland Math 2.NOS.C.7
The Standard
Represent whole number sums and differences within 100 using lengths on a number line.
Maryland College and Career Ready Standards for Mathematics (2025) · USE REPRESENTATIONS, PLACE VALUE UNDERSTANDING, AND PROPERTIES OF OPERATIONS TO ADD AND SUBTRACT.
Teacher's field guide
What This Standard Means
What Students Need to Do
- Students mark a starting number on a number line. They show addition with jumps right and subtraction with jumps left. They label each jump by its length and find where they land.
What Mastery Looks Like
- For 46 + 27, a student starts at 46, jumps 20 and 7 to the right, and lands at 73. For 83 − 35, they jump 30 and 5 to the left and land at 48.
Common Misconceptions
- Some students count tick marks instead of spaces, so a jump of 5 lands one number off. Others move right when subtracting or draw a jump of 20 as only two spaces.
How to Assess It
- Exit ticket: Use a number line to solve 58 − 24. Show and label each jump, then write the difference.
Lesson moves
Ways to Teach It
On a meter stick, place a counter at 42 and lay 20 cm and 3 cm paper strips end to end to show 42 + 23.
Draw jumps for 71 − 26 and explain why you moved left by 20, then 6.
In pairs, start at 50, flip a coin for direction, roll a die for jump length, and sketch five jumps.
Draw a 0 to 100 mile number line for a bus that travels 38 miles, then 25 more; mark both legs and the total.
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Printable 2.NOS.C.7 Worksheet
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Related Standards
- 2.NOS.A.4
Compare two numbers within 1000 by reasoning about the values of the hundreds, tens, and ones digits and/or the location of the numbers on a number line. Record...
- 3.NOS.A.1.d
Compare two whole numbers by reasoning about the values of the digits and the location of the numbers on a number line. Record the results of comparisons with t...
- 1.NOS.B.4
Represent whole numbers as lengths from 0 on a number line (horizontal and vertical) with equally spaced points corresponding to whole numbers.
- 1.NOS.B.5
Compare two numbers within 100 by reasoning about values of tens and ones digits and the location of the numbers on a number line. Record the results of compari...
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