Maryland Math 5.NOS.C.9
The Standard
Solve problems in context involving addition and subtraction of fractions referring to the same whole, including cases of unlike denominators using visual fraction models and/or equations to represent the problem.
Maryland College and Career Ready Standards for Mathematics (2025) · USE EQUIVALENT FRACTIONS AS A STRATEGY TO ADD AND SUBTRACT FRACTIONS.
Teacher's field guide
What This Standard Means
What Students Need to Do
- Students decide whether a story calls for adding or subtracting fractions of the same whole. They rename fractions with a common denominator, then show their work with a bar model or equation.
What Mastery Looks Like
- A student can show that 1/2 cup plus 1/3 cup is 5/6 cup by dividing a bar into sixths. They label the answer with units and check that it fits the story.
Common Misconceptions
- Some students add denominators as well as numerators, making 1/2 + 1/3 equal 2/5. Others draw unequal wholes or subtract numerators and denominators separately instead of renaming the fractions.
How to Assess It
- Exit ticket: A ribbon is 3/4 meter long, and Sam cuts off 1/3 meter; draw a bar model and write an equation for the length left.
Lesson moves
Ways to Teach It
Cut two of three equal strips into thirds and fourths; place one piece of each end to end on the third to find their sum.
Ask, 'Why is 3/7 mile wrong for a walk of 2/3 mile plus 1/4 mile?' Have students draw a bar to explain.
Make pizza cards showing 1/2 plus 1/3 eaten and 3/4 minus 1/2 left; pairs match each to a bar model and equation.
Sketch a trail map with 2/3 mile to a bridge and another 1/4 mile to a pond; students find the total distance.
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Printable 5.NOS.C.9 Worksheet
A ready-to-print activity worksheet aligned to 5.NOS.C.9, with an answer key for the teacher on its own page. No account needed.
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Related Standards
- 4.NOS.E.12.d
Solve problems in context involving addition and subtraction of fractions using visual fraction models and equations to represent the problem.
- 4.NOS.E.13.d
Solve problems in context involving multiplication of a fraction by a whole number, using visual fraction models and equations to represent the problem.
- 4.NOS.E.12
Apply and extend previous understanding of addition and subtraction of whole numbers to add and subtract fractions with like denominators.
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