Math Intervention 3–5 Grade

Addition and Subtraction Concepts 51

What is Missing Part Subtraction?

Missing part subtraction is one of three types of subtraction.

Missing part subtraction involves an unknown part of the

whole. Either the subtrahend or the difference is unknown.

For example, 10 – … = 2 or 10 – 8 = …. Missing part

subtraction is often used to solve start unknown or change

unknown addition problems. For example, … + 2 = 10 or

8 + … = 10. When working with missing part subtraction, it

is important that students use “subtract” rather than “take

away” to more accurately describe the mathematics situation.

CCSS

Operations and Algebraic Thinking

Number and Operations in Base Ten

Formative Assessment

To fi nd out if a student understands missing part subtraction,

ask the student to solve the following number stories;

Melanie has 5 bracelets in her jewelry box. She puts some of the

bracelets on her wrist. There are 2 bracelets left in her jewelry box.

How many bracelets are on her wrist?

An apple tree has 11 beautiful apples. The wind blows 4 apples off

the tree. How many apples are still on the tree?

Lenny bakes 24 cupcakes. He packs a lot of the cupcakes in a box

and leaves 6 on the table. How many cupcakes are in the box?

Missing Part Subtraction

CONCEPT: