Lesson Plan

Explain why fractions with unlike denominators cannot be added or subtracted directly - the pieces are different sizes, so counting them together does not produce a meaningful result

Find a common denominator for two fractions by listing multiples or by multiplying the two denominators

Convert each fraction to an equivalent fraction with the common denominator, applying the principle that multiplying both the numerator and denominator by the same nonzero number does not change the fraction's value

Add fractions with unlike denominators (including mixed numbers) and express the result in simplest form

Subtract fractions with unlike denominators (including mixed numbers) and express the result in simplest form

5.NF.A.1

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.)