Examples, solutions, videos, and songs to help Grade 1 kids learn how to add within 100, including adding a two-digit number and a one-digit number, and adding a two-digit number and a multiple of 10, 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.
Understand that in adding two-digit numbers, one adds tens and tens, ones and ones; and sometimes it is necessary to compose a ten.
Common Core: 1.NBT.4
1.NBT.4 - Add a Two-Digit Number and One-Digit Number
This video explains how to adds a 2-digit number with a 1-digit number. This video illustrates 1.NBT.4 from the Common Core State Standards for Mathematics.
12 + 4 = ?, 13 + 4 = ?, 15 + 4 = ?, 4 + 15 = ?, 12 + 8 = ?, 2 + 18 = ?
1.NBT.4 - Adding a Multiple of 10 to a Two-Digit Number
This video explains how to add a two-digit number and a multiple of 10, using concrete models and strategies based on place value. It uses number discs to show students how to solve the following problems:
42 + 40 = ?, 50 + 36 = ?
Adding 1 and 2 Digit Numbers
72 + 4 = ?, 38 + 5 = ?, 26 + 10 = ?, 55 + 7 = ?, 48 + 10 = ?
Long Addition - 1 by 2 digit numbers without carrying
This video introduces the basic idea to all long addition problems
22 + 3, 34 + 4, 53 + 6, 54 + 5, 92 + 6
Long Addition - 1 by 2 digit numbers with carrying
28 + 5, 37 + 9, 45 + 8, 99 + 9
Adding a 2 digit number and 1 digit with carry
86 + 7 = ?
This video demonstrates adding two digit numbers without regrouping, showing the addition with longs and cubes (base 10 blocks)
24 + 12
This video demonstrates adding two digit numbers with regrouping, showing the addition with longs and cubes (base 10 blocks)
Adding two digit numbers
How to add two 2 digit numbers with a carry.
Adding Two Digit Numbers (with Carrying
Addition Within 100
Grades K-2 / Math / Reasoning
CCSS: Math.1.NBT.C.4 Math.Practice.MP2 Math.Practice.MP3
Use multiple strategies to solve addition problems
The Common Core State Standards (CCSS) videos are designed to support states, schools, and teachers in the implementation of the CCSS. Each video is an audiovisual resource that focuses on one or more specific standards and usually includes examples/illustrations geared to enhancing understanding. The intent of each content-focused video is to clarify the meaning of the individual standard rather than to be a guide on how to teach each standard although the examples can be adapted for instructional use.<
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