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
a.   Ms. Needham made a lasagna for dinner with her family. She cut the lasagna into 12 pieces. Her family ate 4 pieces of lasagna the night that she made it. The next day, they ate 3 more pieces. What fraction of the lasagna did Ms. Needham’s family eat altogether?
b.   Ms. Roll is stringing beads to make a 16-inch necklace. At the end of the first night of working on it, she has 5 inches of beads strung. At the end of the second night of working on it, she has another 7 inches of beads strung. What fraction of the necklace has Ms. Roll completed?
Problem 2
Solve. Show your work with an area model or a number line.
a.
$$\frac{7}{8}+\frac{6}{8}$$
b.
$$\frac{13}{12}+\frac{5}{12}$$
Problem 3
Solve. Show or explain your work.
a.
$${5{1\over8}+{5\over8}}$$
b.
$${9{11\over12}+{11\over12}}$$
c.
$${3{4\over17}+4{8\over17}}$$
d.
$${2{11\over15}+2{13\over15}}$$


aligns: no