standard_description: Use numbers expressed in the form of a single digit times an integer power of 10 to estimate very large or very small quantities, and to express how many times as much one is than the other. For example, estimate the population of the United States as 3 × 108 and the population of the world as 7 × 109, and determine that the world population is more than 20 times larger.
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