Lesson 5

The Digital Clock

Est. Class Sessions: 2

Daily Practice and Problems

Teacher Notes
X

  1. 6 + 2 =  8

    2 + 6 =  8

    8 −  2 = 6

    8 − 6 =  2

  2. 7 + 1 =  8

    1 + 7 =  8

    8 − 1 =  7

     8 − 7 = 1

  3. 4 + 3 =  7

    3 +  4 = 7

    7 −  4 = 3

    7 − 3 =  4

  1. Possible response: You can think 2 + 6 = 8, so you know that
    8 − 2 = 6.

Ongoing Assessment

Use DPP item O to assess students’ abilities to determine the unknown number in an addition or subtraction sentence relating three whole numbers for the facts in Group B [E8].

See the Letter Home for targeted practice ideas.



O. Fact Families

  1. 6 + 2 =

    2 + 6 =

    8 − = 6

    8 − 6 =

  2. 7 + 1 =

    1 + 7 =

    8 − 1 =

    − 7 = 1

  3. 4 + 3 =

    3 + = 7

    7 − = 3

    7 − 3 =

  1. How can you use 2 + 6 to help you answer 8 − = 6?