# Gr. 5 Unit: Perform operations with multi-digit whole numbers and with decimals to hundredths

### Lesson Seed B.7: Addition & Subtraction with Decimals

Essential Questions:

**Lesson Plans and Seeds**

LP 5.NBT.B.5-7 Multiplying Decimals to Hundredths

Lesson Seed B.5: Standard Algorithm for Multiplication Based on Place Value

**Lesson Seed B.7: Addition & Subtraction with Decimals**

**Download Seeds, Plans, and Resources (zip)**

**Content Emphasis By Clusters in Grade 5**

**Progressions from Common Core State Standards in Mathematics**

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Lesson seeds are ideas that can be used to build a lesson aligned to the CCSS. Lesson seeds are not meant to be all-inclusive, nor are they substitutes for instruction. When developing lessons from these seeds, teachers must consider the needs of all learners. It is also important to build checkpoints into the lessons where appropriate formative assessment will inform a teachers instructional pacing and delivery.

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**Lesson Seed: 5.NBT.B.7 Addition and Subtraction with Decimals**

**Standard(s): 5.NBT.B.7** Add, subtract, multiply, and divide decimals to hundredths, using concrete models or drawings and strategies based on place value,
properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method and explain the reasoning used.

**Purpose/Big Idea:**

**Materials:**

**Activity:**

**Exploration**

**1. Addition and subtraction:**Use Base 10 blocks (or use Digi Blocks and adjust) as you work through this activity.

Build original problem. Blue tiles are being added and red tiles are being subtracted.

There are not enough tiles in the tenths column to subtract 0.2, so a 1rod is moved to the tenths column and broken into 10/10.

Subtract each red tenth by placing them on top of the blue tenths.

Subtract the red rod in the 1’s place by placing it on top of the blue rod in the 1’s place.

Have students work several problems until they show an understanding of addition and subtraction of decimals.

**10 x 10 grids**to model (extend to use a 1000’s grid; building on earlier work with equivalent decimals for problems such as 0.31 + 0.415 = 0.310 + 0.415)

__Number line:__

**1. Games:**

**Guiding Questions:**