standard_description: Apply and extend previous understandings of addition and subtraction to add and subtract rational numbers; represent addition and subtraction on a horizontal or vertical number line diagram.
problem_activity: Problem 1
Shade in the grids to represent the following fractions:
|                                  a.                     $${30\over 100}$$                                  |                                  b.                     $${3 \over100}$$                                   |                              c.                     $${{1\over3}\over 100}$$                               |
|------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------|
| .. image:: https://d37su8u1z9ynie.cloudfront.net/uploads/2017/12/18/screen-shot-2017-12-18-at-40254-pm.png | .. image:: https://d37su8u1z9ynie.cloudfront.net/uploads/2017/12/18/screen-shot-2017-12-18-at-40254-pm.png | .. image:: https://d37su8u1z9ynie.cloudfront.net/uploads/2017/12/18/screen-shot-2017-12-18-at-40254-pm.png |
Problem 2
Fill in the chart below to represent equivalent fractions, decimals, and percentages.
| **           Fraction          ** | **           Decimal          ** |   **           Percent          **   |
|-----------------------------------|----------------------------------|--------------------------------------|
|          $$\frac{1}{4}$$          |                                  |                                      |
|                                   |               0.5                |                                      |
|                                   |                                  |                 20%                  |
|          $$\frac{1}{3}$$          |                                  |                                      |
|                                   |               0.05               |                                      |
|          $$\frac{3}{8}$$          |                                  |                                      |
|                                   |               1.3                |                                      |
|                                   |                                  | $$\frac{1}{2}$$                    % |
Problem 3
Use mental math to answer the questions below.
a.
What is 50% of 20?
What is 25% of 48?
What is 10% of 125?
What is 5% of 50?
b.
6 is 50% of what number?
10 is 25% of what number?
9 is 10% of what number?
c.
21 is what percent of 210?
450 is what percent of 900?
20 is what percent of 80?
30 is what percent of 20?


aligns: no