Fifth Grade · Math · week 14

Mixed numbers: add and subtract

Add and subtract mixed numbers with unlike denominators, regrouping when necessary.

A mixed number has a whole-number part and a fraction part. To add mixed numbers, add the whole numbers and the fractions separately (after finding a common denominator), then combine the two results.

Subtracting sometimes needs regrouping: if the fraction you are subtracting is bigger than the one you have, borrow one whole and turn it into an extra fraction piece first.

📋 For the teacher

Teach it (10–15 min):

Separate the two parts clearly on paper -- a whole-numbers column and a fractions column -- so nothing gets mixed up.
Before subtracting, check whether the fraction part will need regrouping by comparing the two fractions first.
Show the borrow physically: one whole unwraps into a fraction with the same denominator as the others, like 1 = 4/4 or 1 = 6/6.
Always convert an improper leftover fraction back into a mixed number in the final answer.

Talk about it:

Why do you add or subtract the whole numbers and fractions in separate parts?
How do you know ahead of time whether you will need to regroup?
What does borrowing one whole actually turn into?

Mastery looks like: They can add and subtract mixed numbers with unlike denominators, regrouping correctly when the fraction being subtracted is larger.

Common stumbles: Subtracting the smaller fraction from the larger one regardless of which mixed number it belongs to; forgetting to convert the borrowed whole into the correct denominator.

See it visually

Interactive, spoken-aloud tools that show this idea in motion.

FractionsSlice bars and circles into equal parts and compare them.try →SubtractionTake away and count back, step by step.try →AdditionSee groups combine — with counters, blocks, and the number line.try →

Homework for this lessonType it, write it with a stylus, or print it for pencil & paper.open →

Records attendance + 15 min of Math for this learner.

← Back to today All courses Year planner