Montana Math MT.5.NF.1
The Standard
Add and subtract fractions with unlike denominators (including mixed numbers) by replacing given fractions with equivalent fractions.
2026 Montana Mathematics Content Standards
Teacher's field guide
What This Standard Means
What Students Need to Do
- Students find a common denominator and rewrite fractions as equivalent fractions. They add or subtract, regrouping mixed numbers when needed.
What Mastery Looks Like
- A student can show why 2 1/4 minus 5/6 equals 1 5/12, including how they regrouped. They check whether the answer makes sense.
Common Misconceptions
- Students may add denominators, writing 1/2 plus 1/3 as 2/5. They may change a denominator without changing the numerator, or forget to regroup before subtracting.
How to Assess It
- Exit ticket: Solve 2 1/4 minus 5/6. Show the equivalent fractions you used and any regrouping.
Lesson moves
Ways to Teach It
Cut paper strips into halves and sixths, then use them to model 1 1/2 minus 2/3.
Ask students to draw a picture explaining why 1/2 plus 1/3 cannot equal 2/5.
Put 1/2, 2/3, 3/4, and 5/6 on cards; partners draw two, add 1 to the first, then subtract the second.
Give students a recipe using 1 1/2 cups of flour and 2/3 cup of oats; ask for the total.
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Printable MT.5.NF.1 Worksheet
A ready-to-print activity worksheet aligned to MT.5.NF.1, with an answer key for the teacher on its own page. No account needed.
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