standard_description: Interpret multiplication as scaling (resizing), by:
- Explaining why multiplying a given number by a fraction greater than 1 results in a product greater than the given number (recognizing multiplication by whole numbers greater than 1 as a familiar case); explaining why multiplying a given number by a fraction less than 1 results in a product smaller than the given number; and relating the principle of fraction equivalence a/b = (n×a)/(n×b) to the effect of multiplying a/b by 1.
- Comparing the size of a product to the size of one factor on the basis of the size of the other factor, without performing the indicated multiplication.
problem_activity: Problem 1
Two different students solved the problem
$$1\frac9{10}+5\frac4{10}$$
below. Study their work and determine whether the strategy they used works.
{"table": [{"_attributes": {"class": ["table"], "style": "width: 100%; layout: fixed"}, "tbody": [{"tr": [{"td": [{"_attributes": {"style": "text-align: center; width: 50%;"}, "strong": [{"_value": "Student A"}]}, {"_attributes": {"style": "text-align: center; width: 50%;"}, "strong": [{"_value": "Student B"}]}]}, {"td": [{"_attributes": {"style": "text-align: center;"}, "img": [{"_attributes": {"src": "https://d21royfkw9g4l6.cloudfront.net/uploads/2022/03/24/g4mathu5l14_at1a.png", "style": "width: 200px; height: 108px;"}}]}, {"_attributes": {"style": "text-align: center;"}, "img": [{"_attributes": {"src": "https://d21royfkw9g4l6.cloudfront.net/uploads/2022/03/24/g4mathu5l14_at1b.png", "style": "width: 125px; height: 140px;"}}]}]}]}]}]}
Problem 2
Two different students solved the problem
$$4\frac38-3\frac68$$
below. Study their work and determine whether the strategy they used works.
{"table": [{"_attributes": {"class": ["table"], "style": "width: 100%;"}, "tbody": [{"tr": [{"td": [{"_attributes": {"style": "text-align: center; width: 50%;"}, "strong": [{"_value": "Student C"}]}, {"_attributes": {"style": "text-align: center; width: 50%;"}, "strong": [{"_value": "Student D"}]}]}, {"td": [{"_attributes": {"style": "text-align: center;"}, "img": [{"_attributes": {"src": "https://d21royfkw9g4l6.cloudfront.net/uploads/2022/03/24/g4mathu5l14_at2a.png", "style": "width: 175px; height: 169px;"}}]}, {"_attributes": {"style": "text-align: center;"}, "img": [{"_attributes": {"src": "https://d21royfkw9g4l6.cloudfront.net/uploads/2022/03/24/g4mathu5l14_at2b.png", "style": "width: 100px; height: 206px;"}}]}]}]}]}]}
Problem 3
Solve.
{"table": [{"_attributes": {"class": ["table", "table-bordered"], "style": "width: 100%;"}, "tbody": [{"tr": [{"td": [{"_attributes": {"style": "text-align: center;"}, "p": [{"span": [{"_attributes": {"class": ["math-tex"]}, "_value": "$$1+\\frac{5}{12}$$"}]}, {"span": [{"_attributes": {"class": ["math-tex"]}, "_value": "$$\\frac{11}{12} + \\frac5{12}$$"}]}]}, {"_attributes": {"style": "text-align: center;"}, "p": [{"span": [{"_attributes": {"class": ["math-tex"]}, "_value": "$$8+4\\frac36$$"}]}, {"span": [{"_attributes": {"class": ["math-tex"]}, "_value": "$$7\\frac56+4\\frac36$$"}]}]}, {"_attributes": {"style": "text-align: center;"}, "p": [{"span": [{"_attributes": {"class": ["math-tex"]}, "_value": "$$1\\frac1{10}-\\frac1{10}$$"}]}, {"span": [{"_attributes": {"class": ["math-tex"]}, "_value": "$$1\\frac1{10}-\\frac2{10}$$"}]}, {"span": [{"_attributes": {"class": ["math-tex"]}, "_value": "$$1\\frac1{10}-\\frac4{10}$$"}]}]}, {"_attributes": {"style": "text-align: center;"}, "p": [{"span": [{"_attributes": {"class": ["math-tex"]}, "_value": "$$6\\frac15-5$$"}]}, {"span": [{"_attributes": {"class": ["math-tex"]}, "_value": "$$6\\frac15-4\\frac45$$"}]}, {"span": [{"_attributes": {"class": ["math-tex"]}, "_value": "$$6\\frac15-4\\frac25$$"}]}]}]}]}]}]}


aligns: no