Primary Standards:
MAFS.1.OA.1.1 Use addition and subtraction within 20 to solve word problems involving situations of adding to, taking from, putting together, taking apart, and comparing, with unknowns in all positions, e.g., by using objects, drawings, and equations with a symbol for the unknown number to represent the problem.
MAFS.1.OA.2.4 Understand subtraction as an unknown-addend problem. For example, subtract 10 – 8 by finding the number that makes 10 when added to 8.
Connecting Standards:
MAFS.1.OA.4.8 Determine the unknown whole number in an addition or subtraction equation relating three whole numbers. For example, determine the unknown number that makes the equation true in each of the equations 8 + ?= 11, 5 = ? – 3, 6 + 6 = ?.
MAFS.1.OA.3.6 Add and subtract within 20, demonstrating fluency for addition and subtraction within 10.
Content Knowledge:
Students are not required to independently read the word problems.
The work in this Unit combines all the 1st grade problem structures experienced in prior Units and expands to work with totals within 20. Students should continue to act out and model the situations from the story problems, both concretely with objects and visually. Students may move through the concrete and visual strategies slightly quicker than their work in prior Units but should still be given the opportunity to continue developing their understanding of the structures with a focus on the actions or comparisons.
Though work in this Unit is not directly focused on fluency, more so the understanding of the structures, models, and related equations, the conceptual base will be applied in further Units focused on building towards gaining fluency. It is far more important for students to focus on the modeling and connections to equations than to “quickly” come up with an answer. Fluency will continue to be built upon for the remainder of the year.
GCG 1: Learning Goal: As a Mathematician, I will be able to Represent and Solve Add To Problems (within 20)
- Step 1: Represent Add To problems with Concrete Tools and drawings (within 20)
- Step 2: Represent Add To problems with Equations (within 20)
GCG 2: Learning Goal: As a Mathematician, I will be able to Represent and Solve Take From Problems (within 20)
- Step 1: Represent Take From problems with Concrete Tools and drawings (within 20)
- Step 2: Represent Take From problems with Equations (within 20)
GCG 3: Learning Goal: As a Mathematician, I will be able to Represent and Solve Put Together/Take Apart Problems (within 20)
- Step 1: Represent and Solve Put Together/Take Apart Problems with Concrete Tools (within 20)
- Step 2: Represent and Solve Put Together/Take Apart Problems (within 20)
- Step 3: Represent and Solve Put Together/Take Apart Problems with Equations (within 20)
GCG 4: Learning Goal: As a Mathematician, I will be able to Represent and Solve Comparison Problems (within 20)