Maryland Math 7.NOS.A.1

7.NOS.A.1 is a cluster heading. These are the individual standards under it.

• 7.NOS.A.1.b

  Model the addition of rational numbers as movement along a number line, where the direction and distance depend on the sign and magnitude of the addend. Show th...

• 7.NOS.A.1.c

  Rewrite subtraction as addition using the additive inverse (p − q = p + (−q)). Use strategies such as number lines and applying absolute value of the difference...

• 7.NOS.A.1.d

  Model and solve multistep contextual problems involving addition and subtraction of rational numbers, using efficient and flexible strategies.

01

What Students Need to Do

Students add and subtract positive and negative fractions and decimals using number lines and other strategies. They rewrite subtraction as adding the opposite and explain why opposite amounts cancel to zero. They find distances between numbers and solve problems with several steps.

02

What Mastery Looks Like

A student can draw -2.5 - (-1.5) as -2.5 + 1.5 and land at -1. They can explain why 1.5 and -1.5 add to zero. They can find the distance between -2.5 and 1.5 as 4.

03

Common Misconceptions

Some students subtract a negative and move left instead of right. Others say the distance from -3 to 2 is -5 because the starting point is negative. They may add 4 and -4 as if both numbers were positive.

04

How to Assess It

Exit ticket: The temperature starts at -3°C, rises 5°C, then drops 1°C. Show the changes on a number line, find the final temperature, and rewrite the subtraction for the distance from start to finish as addition.

1. 01

   Tape a number line to the floor; students walk from -2, add 5, then add -3 and record each landing.

2. 02

   Ask, "Why does 4 + (-4) land at 0, while 4 - (-4) does not?" Have students sketch both moves.

3. 03

   Give pairs expression cards such as -2.5 - (-1.5); they rewrite each as addition and check their answers on a number line.

4. 04

   Show a bank balance of -$12, a $20 deposit, and a $5 withdrawal; students find the new balance and its distance from zero.

• 7.NOS.A.2

  Multiply and divide rational numbers using multiple strategies and representations.

• 7.NOS.A.3

  Solve multistep problems involving positive and negative rational numbers in any form (i.e., fractions, decimals, percents) using all four operations.