PHET
Make a Ten
Rate the resource as a perfect 10. Pupils use an interactive to help add and subtract numbers. They first explore how to express whole numbers using hundreds, tens, and ones, then explore how to add whole numbers by combining to make...
Primary Junction
Adding Tens
Build on your learners' confidence in quick addition as they discover strategies to add tens to two-digit numbers. After reviewing counting by 10's, they discuss tactics to add multiples of 10 to other numbers. They visualize how to...
Houghton Mifflin Harcourt
Mental Math: Subtract Tens - Homework 12.1
Now that your class can add by 10s they can start subtracting by 10s. This clear, learner-friendly worksheet provides a good example (10-rods are pictured) and 7 problems to solve. Relates groups of tens to single-digit numbers, which...
Curriculum Corner
Back to School Math and Literacy Centers
From filling in the missing number to filling in the missing letter; to writing fluency sentences to skip counting and matching, a complete set of back to school math a literacy centers will not disappoint. Use these activities during...
Illustrative Mathematics
Comparing Numbers
Young mathematicians spin their way to a deeper number sense with this fun, collaborative activity. Using two spinners, one with the numbers 0-9 and the other with the decades 00-90, pairs of students take turns building and comparing...
Curated OER
Mentally Add Larger Numbers
Using what they know about adding 10s and 100s, learners attempt to mentally solve 18 addition problems. Each problem requires them to think of the nearest 10 or 100, add them together, then add the remaining units.
West Contra Costa Unified School District
The Power of Ten: Building a Magnitude Model
Add visual representation to teaching place value with a magnitude model. Using adding machine tape, pupils build a linear place value strip from 1 to 100.
Houghton Mifflin Harcourt
Curious George Learns to Count
The magic number is 100. A collection of fun activities, this guide provides educators with ideas for young mathematicians to practice counting to 100.
Math Learning Center
Addition Strategies
Help young mathematicians refer to simple addition strategies with a set of math posters. The pages feature ways to remember how to add zero to a number, how to determine if a number is odd or even, and making fast tens.
CK-12 Foundation
Mental Math to Multiply by Whole Number Powers of Ten: The Rule for Tens
Eight questions challenge scholars to use mental math while multiplying whole numbers by powers of 10. A tool with bouncing decimals demonstrates how and where the decimal moves. Question types include several multiple-choice, a...
Curated OER
Mental Math: Adding 10s
To develop mental math skills for adding 10s, learners read an example, solve one carefully scaffolded problem, and then complete 6 more independently. Pictures of 10-rods make the connection between sets of 10 and the corresponding...
Los Angeles County Office of Education
Assessment for the California Mathematics Standards Grade 1
Here is an assessment designed to test mathematicians' knowledge of writing numbers, comparing numbers, skip counting, solving addition and subtraction problems; along with measuring objects, telling time, identifying shapes, reading...
Illustrative Mathematics
Party Favors
Pia is putting stickers into party bags. She starts by putting 10 stickers in each bag, and over the course of a week she adds several bundles of ten stickers to each bag, as well as making more bags. Second graders must find the number...
Curated OER
Working with 10s and 1s, Part 2
Practice place value by visualizing 10s and 1s. First graders count the cubes in each place, then write the total number at the bottom. In one particularly helpful section, they draw the cubes that will add up to a given number. Bring in...
Curated OER
How to Use Expanded Form
Third graders write numbers in expanded form. In this math vocabulary lesson, 3rd graders write numbers in expanded form using words only, words and numbers, and numbers only. Each student is given three dice to roll. They then write the...
Curated OER
Grade 3: Make a Hundred
Third graders roll a die seven times, each time determining whether to add that number of tens or that number of ones to try to make a sum as close to 100 as possible without going over.
Smithsonian Institution
The Soldier’s Experience—Vietnam versus World War I
The Vietnam War and World War I were two very important—and different—wars. To understand the differences, and similarities, class members watch videos, examine primary source documents, and then create a newscast that examines the...
Granite School District
Activities that Build Number Sense
Have fun while building the number sense of young mathematicians with this list of ten-frame learning games. From developing cardinality and counting skills to learning place value and basic addition strategies, ten-frames are excellent...
Curated OER
Make a Match
Second graders examine the relationship between addition and subtraction. In this number sense lesson, 2nd graders practice their computation skills and use various strategies (including manipulatives and calculators) to add and subtract.
Willow Tree
Rational vs. Irrational Numbers
Build an understanding of rational numbers and their counterpart irrational numbers. Lead learners through an explanation of rational numbers and the ways they can be expressed. Then introduce them to irrational numbers and make...
Innovative Mobile Apps
Action Words
From asking to yelling, this app teaches action verbs through images. Users listen to each word and tap the picture that corresponds with that verb. Just touch the screen to get started!
Curated OER
Developing Strategies for Addition and Subtraction
Primary graders develop strategies to assist them with addition and subtraction. They discover number combinations and numerical facts which enable them to add and subtract more effectively. Students use these techniques to complete...
Curated OER
Addition Practice #1
Show young mathematicians that they are fully capable of mentally adding two-digit numbers. They start by solving 12 two-addend problems (all with two-digit numbers and aligned horizontally). There is no room to show work. Consider...
Curated OER
Ones and Tens Place Value
As scholars examine place value, these exercises help them incorporate addition and grouping. First, they answer three missing-addend questions, each with 10 as the given addend. Because all of the missing numbers are single-digit, this...