Primary Standards:
MAFS.K.OA.1.4 For any number 1 to 9, find the number that makes 10 when added to the given number, e.g. by using objects or drawings, and record the answer with a drawing or equation.
Connecting Standards:
MAFS.K.OA.1.1 Represent addition and subtraction with objects, fingers, mental images, drawings, sounds (e.g., claps), acting out situations, verbal explanations, expressions, or equations.
MAFS.K.OA.1.2 Solve addition and subtraction word problems, and add and subtract within 10, e.g., by using objects or drawings to represent the problem.
Content Knowledge:
One of the big ideas about our number system is that numbers are flexible, they can be broken apart (decomposed) and put together (composed) flexibly. In addition to gaining insight about how numbers work, composing and decomposing numbers builds on the understanding of addition and subtraction.
Exploring the addends that form 10 is particularly important. The understanding, and eventually memory, of addends that combine to make 10 allows students to do mental computations more easily. At the kindergarten level, the focus is on finding the other addend that makes 10 when given a number 1-9. Kindergarteners do not need to obtain fluency with these compositions, in first grade they will work on committing these to memory.
In this Unit, students will begin exploring these compositions of 10 by modeling with objects and pictorial representations on ten-frames and with part-part-whole models. Eventually they will transfer this knowledge to the more abstract strategy of number bonds. However, some students may need more time working with concrete objects even as transitioning to recording with number bonds.
GCG 1 – Learning Goal: As a Mathematician, I will be able to Compose a Ten by Using a Ten Frame
- Step 1: Students can use tools on a ten frame to determine the number to add to compose a 10
- Step 2: Students can represent their solution to compose ten (when one addend is provided) by drawing on a ten-frame
- Step 3: Students can match their representations of ten to provided expressions or equations
GCG 2 – Learning Goal: As a Mathematician, I will be able to Compose a Ten Using the Part-Part-Whole Model
- Step 1: Students can compose a ten by using a part-part-whole model (number bond) with tools to determine the number to make 10
- Step 2: Students can compose a ten by using a drawing to represent a part-part-whole model (number bond) to determine the number to make 10
- Step 3: Students can compose a ten by matching their representations to provided expressions or equations