Number and Operations in Base 10: Addition within 100 CCSS 2.NBT.5(1) Worksheets & Activities

Help students learn to fluently add within 100 using strategies based on place value, properties of operations, and/or the relationship between addition.

See the fact file below for more information on addition within 100 or alternatively, you can download our 23-page Number and Operations in Base 10: Addition within 100 worksheet pack to utilise within the classroom or home environment.

Key Facts & Information

Learning Objective

At the end of the lesson, the student will fluently add within 100 using strategies based on place value, properties of operations, and/or the relationship between addition.

A Note for the Teacher

When adding within 100, take note of the following:

• You are dealing with up to two-digit addends
• Decompose the addends into tens and ones
• Remember that adding means having a value that is greater than both addends
• Vertically, always start adding from the ones, then tens

Theory

When adding numbers within 100, we can simply decompose the addends and add by place values.

• Consider 48 + 34:
  First, decompose 48 and 34 into place values.
  48 = 4 tens + 8 ones = 40 + 8
  34 = 3 tens + 4 ones = 30 + 4

• Next, add the place values.
  4 tens + 3 tens = 70 = 40 + 30
  8 ones + 4 ones = 12 = 8 + 4

• If the sum of the one place becomes a two-digit, decompose again.
  12 = 1 tens + 2 ones = 10 + 2

• Then, add by place values again
  70 + 10 = 80

• Lastly, put them all together.
  80 + 2 = 82

• You can also solve it vertically:

Next,

Lastly,

Numbers and Operations in Base 10: Place Value – Comparing 3 Digit Numbers Worksheets

This is a fantastic bundle that includes everything you need to know about Numbers and Operations in Base 10: Place Value – Comparing 3 Digit Numbers 23 in-depth pages. These are ready-to-use worksheets that align with the Common Core code 2.NBT.5(1) for Comparing 3 Digit Numbers.

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Complete List of Included Worksheets

• A lesson plan
• Warm-up activity
• Math theory explained
• Assisted learning activities
• Independent learning activities
• Extension activities and games
• Answer keys

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