Primary Standards:
MAFS.1.OA.1.1 Use addition and subtraction within 20 10 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.3.5 Relate counting to addition and subtraction (e.g., by counting on 2 to add 2).
MAFS.1.OA.3.6Add and subtract within 20, demonstrating fluency for addition and subtraction within 10.
Content Knowledge:
Students are not required to independently read the word problems.
In kindergarten, students mainly solved word problems with the total unknown. A challenge at first grade is solving problems with the unknown in any position. Now, instead of looking for the sum, there might be other data missing from the problem. To build understanding of these new problem structures, this Unit will focus on problems involving totals within 10.
This Unit will include problem structures students have worked with in kindergarten (Add To – Result Unknown, Take From – Result Unknown, Put Together/Take Apart – Total Unknown & Both Addends Unknown) as well as introduce the new structures Add To – Change Unknown, Take From – Change Unknown, & Put Together/Take Apart – Addend Unknown. Students should be given the opportunity to solve these problems by acting out, directly modeling with objects, retelling the stories, drawing pictures, and writing equations to connect to the actions in the story problems.
Students in this Unit will also work with equations with unknowns in different positions to represent the problems. They continue to work with different symbols to represent the unknowns, such as questions marks or empty boxes. In this Unit, students are not expected to show mastery with writing equations, though they may begin to write their own.
GCG 1 – Learning Goal: As a Mathematician, I will be able to Represent and Solve Add To Problems within 10 MAFS.1.OA.1.1
- Step 1: Represent Add To problems with Concrete Tools within 10
- Step 2: Represent Add To problems within 10
- Step 3: Represent Add To problems with Equations within 10
GCG 2 – Learning Goal: As a Mathematician, I will be able to Represent and Solve Take From Problems within 10 MAFS.1.OA.1.1, MAFS.1.OA.2.4
- Step 1: Represent Take From problems with Concrete Tools within 10
- Step 2: Represent Take From problems within 10
- Step 3: Represent Take From problems with Equations within 10
GCG 3 – Learning Goal: As a Mathematician, I will be able to Represent and Solve Put Together/Take Apart Problems MAFS.1.OA.1.1, MAFS.1.OA.2.4