standard_description: 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. (Students who can generate equivalent fractions can develop strategies for adding fractions with unlike denominators in general. But addition and subtraction with unlike denominators in general is not a requirement at this grade.) For example, express 3/10 as 30/100, and add 3/10 + 4/100 = 34/100.
Grade 4 expectations in this domain are limited to fractions with denominators 2, 3, 4, 5, 6, 8, 10, 12, and 100.
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.
|                          **             Student A            **                          |                          **             Student B            **                          |
|------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------|
| .. image:: https://d21royfkw9g4l6.cloudfront.net/uploads/2022/03/24/g4mathu5l14_at1a.png | .. image:: https://d21royfkw9g4l6.cloudfront.net/uploads/2022/03/24/g4mathu5l14_at1b.png |
Problem 2
Two different students solved the problem
$$4\frac38-3\frac68$$
below. Study their work and determine whether the strategy they used works.
|                           **            Student C           **                           |                           **            Student D           **                           |
|------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------|
| .. image:: https://d21royfkw9g4l6.cloudfront.net/uploads/2022/03/24/g4mathu5l14_at2a.png | .. image:: https://d21royfkw9g4l6.cloudfront.net/uploads/2022/03/24/g4mathu5l14_at2b.png |
Problem 3
Solve.
| $$1+\frac{5}{12}$$                          $$\frac{11}{12} + \frac5{12}$$ | $$8+4\frac36$$                          $$7\frac56+4\frac36$$ | $$1\frac1{10}-\frac1{10}$$                          $$1\frac1{10}-\frac2{10}$$                          $$1\frac1{10}-\frac4{10}$$ | $$6\frac15-5$$                          $$6\frac15-4\frac45$$                          $$6\frac15-4\frac25$$ |
|----------------------------------------------------------------------------|---------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------|


aligns: no