Fifth Grade Mathematics
Unit 5
Addition and Subtraction of Fractions

Printable Parent Letter

During Unit 5, your children will apply their understanding of fractions and fraction models to represent the addition and subtraction of fractions with unlike denominators as equivalent calculations with like denominators. They will develop fluency in calculating sums and differences of fractions, and make reasonable estimates of them.
 

Students need to:

  • 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.
  • Solve word problems involving addition and subtraction of fractions referring to the same whole, including cases of unlike denominators, e.g., by using visual fraction models or equations to represent the problem. Use benchmark fractions and number sense of fractions to estimate mentally and assess the reasonableness of answers.
  • Make a line plot to display a data set of measurements in fractions of a unit (12, 14, 18). Use operations on fractions for this grade to solve problems involving information presented in line plots. For example, given different measurements of liquid in identical beakers, find the amount of liquid each beaker would contain if the total amount in all the beakers were redistributed equally.

Carroll County Public Schools Video Support


Adding Fractions with Unlike Denominators

Ways Parents Can Help

  • The website listed to the right is the national library of virtual manipulatives. This site will provide your child with practice adding fractions with like and unlike denominators by taking them through steps that include using fraction manipulatves while they solve the problem.
  • When cooking includes using fractional measurements have your child figure out total amounts added into the recipe. For example, ½ cup sugar and ¾ cup flour would total 5/4 or 1 ¼ cups.
  • Create real world problems involving food that is already partitioned into equal pieces (e.g. pizza, a cake, Hershey’s chocolate bar). An example of a problem might be: I ate ¼ of the pizza and you ate 3/8 of the pizza. How much did we eat together and how much of the pizza is left? ¼ = 2/8 2/8 + 3/8 = 5/8 8/8 – 5/8 = 3/8

Some Support Sites

National Library of Virtual Manipluatives

 

Key Vocabulary to Know

Unit fraction

Numerator

Denominator

Proper fraction

Improper fraction

Mixed number

Multiple

Inverse

Factor

Product

Expression

Equation

Benchmark fractions

Identity property

Reflexive property of equality a=a