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STOPIC B:
STOPIC B:
Addition and Subtraction of Fractions by Making Like Units
Addition and Subtraction of Fractions by Making Like Units
Dear Family,
In grade 4, your student learned to add and subtract fractions with the same units, or same
denominators. Now, they extend their understanding to add and subtract fractions with
different units, or different denominators such as thirds and fourths. They use models and
equations to find a common unit before adding or subtracting. Your student is encouraged
to think about equivalent ways to show their answer, such as 9/6 or 3/2 or 1 and 1/2, but they are not
expected to provide the answer in a specific way.
KEY TERMS
centigram
centiliter
exponent
exponential form
kiloliter
milligram
millimeter
powers of 10
AT HOME ACTIVITY
Measuring Cup Fractions
Provide your student with a set of measuring cups. Ask questions to help them practice finding a common unit before adding and subtracting fractions. The measuring cups can be used for reference. Your student can also practice measuring with materials, such as flour, dry rice,
sugar, or water.
• “How many cups of flour would we have in a bowl if we put in 1/2 cup of flour and then put 1/3 cup of flour?)
ANSWER: (5/6 cups of flour)
• “Suppose I put 3/ 4 cups of water into a bowl and then realized that it is 1/3 cup too much. How much would be left after I remove the 1/3 cup of water?"
ANSWER: (5/12 cups of water)
Fraction Time
Amounts of time can be expressed as fractions of an hour (10 minutes is 1/6 of an hour, 15 minutes is 1/4 of an hour, 20 minutes is 1/3 of an hour, and 30 minutes is 1/2 of an hour). Use fractions of an hour to help your student think about making like units when adding and subtracting fractions.
• If your student takes 1/ 4 of an hour (15 minutes) to take a shower and 1/6 of an hour (10 minutes) to get dressed, ask them to tell you the total amount of time they spend on the activities as a fraction of an hour. 1/4 + 1/6 = 5?12, so they spend 5/12 of an hour, or 25 minutes, showering and getting dressed.
Find a sample of our lessons below to help support MATH TALK at home.
Students also have these in their APPLY workbook.
Lesson 5
Add and subtract fractions with related units by using pictorial models.
When I add or subtract fractions with related units, I can use tape diagrams to find equivalent fractions with like units. Then I can represent the sum or difference on a number line.
EM2_G5_M2_TB_L05_PracticePartner.pdfEM2_G5_M2_TB_L05_PracticeSolutions.pdfLesson 6
Add and subtract fractions with related units by using area models to rename fractions.
When I add or subtract fractions with related units, I can use area models to find equivalent fractions with like units. When I compose small units into larger units, I can record my thinking by using division. When I decompose large units into smaller units, I can record my thinking by using multiplication.
EM2_G5_M2_TB_L06_PracticePartner.pdfEM2_G5_M2_TB_L06_PracticeSolutions.pdfLesson 7
Add and subtract fractions with related units by finding equivalent fractions numerically.
When I add or subtract fractions with related units, I can visualize an area model to help me think about how to make equivalent fractions. I can multiply or divide the numerator and denominator of a fraction to make equivalent fractions with like units before I add or subtract.
EM2_G5_M2_TB_L07_PracticePartner.pdfEM2_G5_M2_TB_L07_PracticeSolutions.pdfLesson 8
Add and subtract fractions with unrelated units by finding equivalent fractions pictorially.
When I add or subtract fractions with unrelated units, I can use area models to find equivalent fractions with like units.
EM2_G5_M2_TB_L08_PracticePartner.pdfEM2_G5_M2_TB_L08_PracticeSolutions.pdfLesson 9
Add and subtract fractions with unrelated units by finding equivalent fractions numerically.
When I add or subtract fractions with unrelated units, I can compose or decompose units to find equivalent fractions with like units. I can show my thinking about equivalent fractions numerically and write equations to find sums or differences.
EM2_G5_M2_TB_L09_PracticePartner.pdfEM2_G5_M2_TB_L09_PracticeSolutions.pdfReport abuse