Lesson 4

Subtraction with Base-Ten Pieces

Est. Class Sessions: 2

Daily Practice and Problems

Teacher Notes
X

Emily is right. Possible response: 0–3 doesn’t make sense. Mara just switched the numbers around.

Ongoing Assessment

Use DPP item L to assess students’ abilities to determine the unknown number in an addition or subtraction sentence relating three whole numbers for the facts in Group A [E7].

L. Fact Families

Mara and Emily recorded the fact family for 0, 3, and 3.

Mara’s work                                      Emily’s work

3 − 0 = 3                                            3 − 0 = 3

0 − 3 = 3                                            3 + 0 = 3

3 + 0 = 0                                            0 + 3 = 3

0 + 3 = 3                                            3 − 3 = 0

Mara and Emily noticed that their work did not match. Who is right? How do you know?