Lesson 5

Subtracting Multidigit Numbers

Est. Class Sessions: 3

Daily Practice and Problems

Teacher Notes
X

Have students share solution strategies. Have number lines readily available.

  1. 23 cc; Possible response:
    50 + 23 = 73 or 73 − 50 = 23
  2. 25 cc; Possible response:
    73 + 25 = 98 or 98 − 73 = 25
  3. Responses will vary. Possible responses: Yes, the water will go over 100 cc, because the two rocks have a volume of 106 cc, 47 + 59 = 106, and there is 50 cc of water in the cylinder for a total of 156 cc.

V. Volume Problem

Frank has a collection of colorful rocks. He is finding the volume of his rocks with a 100-cc graduated cylinder and 50 cc of water. Include units.

  1. Frank put a blue rock into the cylinder and saw the water was at 73 cc.

    What is the volume of the blue rock? _______________________

    Number sentence _____________________________________
  2. He forgot to take the blue rock out of the water and added a green rock. This time the water rose to 98 cc.

    What is the volume of the green rock? _______________________

    Number sentence _____________________________________
  3. Frank removed both rocks and put a yellow and a red rock in together. The yellow rock has a volume of 47 cc and the red rock has a volume of 59 cc.

    Do you think the water spilled over the top of the graduated cylinder? Show or tell how you know.