Add and subtract fractions with unlike denominators. Have students write the intermediate step. For example, 2/3 + 5/4 = 8/12 + 15/12 = 23/12.

Watch these Khan Academy videos:

- Adding and subtracting 3 fractions
- Solving for the missing fraction
- Subtracting mixed numbers: 7 6/9 - 3 2/5
- Adding mixed numbers: 19 3/18 + 18 2/3
- Subtracting fractions with unlike denominators
- Visually adding fractions: 5/6+1/4
- Visually subtracting fractions: 3/4-5/8
- Adding fractions with unlike denominators
- Adding mixed numbers with regrouping
- Subtracting mixed numbers with regrouping (unlike denominators)

Do these Khan Academy exercises:

- Add and subtract fractions
- Add and subtract mixed numbers with unlike denominators (no regrouping)
- Subtracting fractions with unlike denominators
- Visually add and subtract fractions
- Add fractions with unlike denominators
- Estimate to add and subtract fractions with different denominators
- Add and subtract mixed numbers with unlike denominators (regrouping)
- Equivalent expressions with common denominators

Next, give your students this challenge:

In each of the problems below, you're given 4 cards, each containing a single digit. Place the 4 cards to make two two-digit numbers, that give the largest possible product.

Here's the answer.

Conclude by leading this investigation:

Lazy Lemur Puzzles

by MathPickle

5.NF.A.1: Add and subtract fractions with unlike denominators (including mixed numbers) by replacing given fractions with equivalent fractions in such a way as to produce an equivalent sum or difference of fractions with like denominators. *For example, 2/3 + 5/4 = 8/12 + 15/12 = 23/12. (In general, a/b + c/d = (ad + bc)/bd.)*