Unit 6 Contents

These problems do not need exact answers. Try to use mental math, a number line, or other quick strategies to make estimates. Be ready to explain your thinking.

1. The third-grade classes at Bessie Coleman School decided to put on a play for their families. On the first night of the play, two classes decorated with balloons. One class used 156 balloons. The other class used 138 balloons.
   
   Estimate the total number of balloons used by the two classes. Do you think the total is closer to 200, 300, or 400? Why?
2. Frank and Nisha covered hats with fancy material. Frank needed 1235 square centimeters of material for his hat. Nisha's hat needed 73 square centimeters more than Frank's hat.
   
   Estimate the amount of material needed for Nisha's hat. Is it closest to 1200, 1250, or 1300 square centimeters?
3. Students sold tickets for the first night of the play. Emily sold 128 tickets, Rosa sold 203, and Kim sold 198. There are 550 seats in the theater. Will there be enough seats? How do you know?

4. Fern and Josh measured the distance across the stage for a string of lights. Fern measured from the right side and Josh from the left. When they met, Fern had measured 327 cm and Josh had measured 273 cm. They have a string of lights 500 cm long. Is it long enough to go across the stage? Why or why not?
5. The students had a bake sale to pay for the costumes. Students brought in cookies. Mrs. Hunter's class brought in 194 cookies, and Mr. Martin's class brought in 235.
1. About how many cookies do they have altogether?
2. If Mrs. Hunter's class brought in 100 more cookies, would they have more cookies than Mr. Martin's class? How do you know?