​Fourth Grade Mathematics
Unit 4
Addition and Subtraction of Fractions

Printable Parent Letter

During Unit 4, your child will build upon his knowledge of fractions and the base-ten system to develop an understanding of decimals to the hundredths place.  The relationship between fractions and decimals is formed using visuals including area models, grids, and number lines and is used to develop students’ understanding that decimals (like fractions) can be used to name values less than 1 or values between whole numbers.  Additionally, your child will utilize whole number patterns in the base-ten system and extend them to the right of the ones place with decimals.  Fourth graders will apply their understanding of equivalent fractions and decimals in order to understand relative size and to compare/order and add/subtract decimals. They will make connections between adding/subtracting fractions as they apply these concepts to word problems and line plots involving measurement data.  They will add and subtract fractions with the same denominator and convert an improper fraction to a mixed number by decomposing the fraction into a sum of a whole number and a number less than 1.   Throughout this unit, students will build a deep number sense of fraction and decimal numbers.

Students need to:

  • Add and subtract mixed numbers  with like denominators, e.g., by replacing each mixed number with an equivalent fraction, and/or by using properties of operations and the relationship between addition and subtraction.
  • Solve word problems involving addition and subtraction of fractions referring to the same whole and having like denominators, e.g., by using visual fraction models and equations to represent the problem.
  • Make a line plot to display a data set of measurements in fractions of a unit (1/2, 1/4, 1/8). Solve problems involving addition and subtraction of fractions by using information presented in line plots.
  • Express a fraction with denominator 10 as an equivalent fraction with denominator 100, and use this technique to add two fractions with respective denominators 10 and 100.  For example, express 3/10 as 30/100 and add 3/10 + 4/100 = 34/100
  • Use decimal notation for fractions with denominators 10 or 100. For example, rewrite 0.62 as 62/100; describe a length as 0.62 meters; locate 0.62 on a number line diagram.
  • Compare two decimals to hundredths by reasoning about their size. Recognize that comparisons are valid only when the two decimals refer to the same whole. Record the results of comparisons with the symbols >, =, or <, and justify the conclusions, e.g., by using a visual model

Carroll County Public Schools Video Support

Miksa Fraction Number Line
Equivalent Fractions on a Number Line

Keegan Adding Line Denominators Keegan Adding Fractions
Addition of Fractions with Like Denominators

Dorsey Connecting Fractions and Decimals
Connecting Fractions to Decimals

Miksa Decimal Digis
Represting Decimls with Digi Blocks

Ways Parents Can Help

  • Involve your child in cooking activities. Have them select the appropriate measuring spoons and cups for the recipe. If ingredients need to be doubled or halved, ask them to figure out what the new quantity would be for the recipe.
  • Dollars and cents provide a real-world example of decimal numbers. Have your child count a handful of coins. Relate the number of 10- cent equivalents to tenths of a dollar and the number of cents to hundredths of a dollar. Ask your child what the fraction equivalent of the coins would be …$0.64 can be expressed as 6 dimes and 4 pennies or 64/100 of a dollar.
  • Statistics in baseball, basketball, swimming, and football provide a great opportunity to discuss decimal numbers and how they relate to sports’ players’ performance. Have your child get active and do math, too, by taking ten basketball shots or baseball swings and counting how many baskets or hits are made. Express the results as a fraction and a decimal. Ex. Six shots made out of ten …6/10 or 0.6.

Some Support Sites



Key Vocabulary to Know





Equivalent Fraction



Improper fraction


Mixed number


Line plot





Unknown Value