Decomposing Numbers to 10

Kindergarten MathAddition and Subtraction4 pages

About this worksheet

Decomposing Numbers to 10 targets one Common Core standard, K.OA.3, through three number sizes. Fish bowls open the sheet: one bowl holds 2 fish swimming left and 3 swimming right, another holds 4 and 1, and students record 5 = 2 + 3 and 5 = 4 + 1. Two rows of 7 circles come next, and students color some in each row to invent two different ways to make 7. The sheet finishes with ten-frames showing 6 filled and 4 empty spots, then 8 filled and 2 empty, each recorded as a 10 = __ + __ equation. The key lists all six valid pairs for 7.

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$Decomposing Numbers to 10: Addition and Subtraction - page 1$

$Decomposing Numbers to 10: Addition and Subtraction - page 2$

$Decomposing Numbers to 10: Addition and Subtraction - page 3$

$Decomposing Numbers to 10: Addition and Subtraction - page 4$

Curriculum objectives covered

K.OA.3

“Decompose numbers less than or equal to 10 into pairs in more than one way, e.g., by using objects or drawings, and record each decomposition by a drawing or equation (e.g., 5 = 2 + 3 and 5 = 4 + 1).”

The sheet is this standard end to end: 5 breaks into 2 + 3 and 4 + 1 exactly as the standard's example reads, 7 breaks two student-chosen ways, and 10 breaks into 6 + 4 and 8 + 2.

What's inside this worksheet

Part 1: Break Apart 5

Two fish-bowl pictures split 5 by swimming direction. Students count 2 fish going left and 3 going right, then 4 and 1, and complete 5 = __ + __ for each bowl.

Part 2: Two Ways to Make 7

Rows labeled Way A and Way B each hold 7 blank circles. Students color some and leave the rest white, then write a matching equation for each way; the two ways must differ.

Part 3: Ten-Frame Partners to 10

Two ten-frames show filled and empty spots (6 and 4, then 8 and 2). Students count both kinds, write the counts on the lines, and finish the equation 10 = __ + __.

How teachers use it

Introducing decomposition

The fish bowls give the part-part-whole idea a physical cue, swimming left versus right. Start here before the more abstract coloring task.

Checking for real understanding

Part 2 is the tell. The key accepts any pair from 1 + 6 to 6 + 1, but Way B must differ from Way A; students who repeat their first pair have a procedure, not the concept.

Ten-frame bridge

Use Part 3 right before making-10 lessons. Counting empty spots as a part, 4 empty in the first frame, is the exact move that missing-addend work will demand.

More Kindergarten Math worksheets

Counting and Cardinality Numbers in Base Ten Measurement and Data Geometry

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