Illustrative Mathematics
What’s Missing?
Now you see them, now you don't! This fun peek-a-boo activity engages young mathematicians in developing their ability to compose and decompose numbers. After being presented with a series of counters, children close their eyes while the...
Illustrative Mathematics
Three Composing/Decomposing Problems
Practice composing and decomposing numbers in base-ten using three word problems. Each problem presents a different scenario requiring learners to explain their thinking, find the number of ones, and find out different ways to make a...
Illustrative Mathematics
Shake and Spill
Entertaining as well as educational, this math activity about decomposing numbers is bound to capture the engagement of young learners. Given a cup and five two-color counters, young mathematicians simply shake and spill the cup,...
Illustrative Mathematics
Overlapping Rectangle
Challenge young mathematicians' ability to compose and decompose shapes with this fun geometry puzzle. The goal is simple, locate all of the rectangles shown in a picture of three overlapping rectangles. Perform this activity as a whole...
Math Worksheets Land
Decomposing Numbers Guided Lesson
Guide your young mathematicians through an exercise in composing and decomposing numbers from 0 to 10. The prompts ask learners to match an addition sentence to the model, to select which of the equations makes 9, and which one makes 6....
K20 LEARN
Decomposers—Fraction Style: Fractions
"What are fractions composed of?" is the essential question of a lesson designed to enhance understanding and strengthen the foundation of adding fractions. Mathematicians start by discussing what makes an equation true or false, then...
Illustrative Mathematics
Make Your Own Puzzle
Puzzling over what geometry lesson to teach next? Look no further. This simple activity teaches young mathematicians how shapes can be decomposed into smaller figures, and how smaller figures can be assembled into larger shapes. To learn...
Illustrative Mathematics
Pick Two
Learning to break apart numbers into smaller pairs is a critical step young mathematicians take as they develop their number sense. To practice this skill, children are provided with sets of three numbers and are asked to pick the two...
Curated OER
Decomposing Numbers Step-By-Step
Here are two addition-related exercises. However, bear in mind, the explanations are featured below each of them. Use this as an all-class warm up, revealing the explanations if and when you see fit. First, examine the four sets of...
Curated OER
Building Sets of 13 and 14
Compose and decompose sets of 13 and 14 and compare sets of each with your little learners. They use objects to construct sets of 13 and 14, record their answers, and compare sets in several different ways.
Curated OER
Addition and Subtraction up to 100
After reviewing double-digit addition and subtraction up to and from 100, learners are introduced to addition and subtraction up to and from 10,000. A grid is used along side number decomposition to help them solve a word problem...
Noyce Foundation
Apple Farm Field Trip
Monitor the growth of young mathematicians with a comprehensive addition and subtraction assessment. Using the context of a class field trip to an apple orchard, this series of four story problems allows children to demonstrate their...
Houghton Mifflin Harcourt
Numbers 11-19
Develop the concept that numbers from 11 to 19 are essentially a 10, plus more! The first two of the six story problems on this sheet are scaffolded with pictures. Learners compose and decompose numbers to answer how many 10s and how...
Scholastic
Study Jams! Light Absorption, Reflection, & Refraction
Zoe and RJ are trying to photograph an egret on a lake, but they are having trouble with the lighting. Reflection, refraction, and absorption are explored through their thoughtful dialogue so that your physical scientists are illuminated...
ISTE
Let's Count to 10
Learners form groups of zero to 10 objects. They connect number names to groups, compose and decompose numbers, and use numerals to record the size of a group. The comprehensive, eight-component mini unit addresses the needs of visual,...
Utah Education Network (UEN)
Geo Shapes
Invite your first graders to compose and decompose two and three-dimensional figures with this fun, hands-on lesson. They investigate and predict the results of putting together and taking apart two-dimensional shapes with rubber bands...
Illustrative Mathematics
Counting Squares
Challenge young mathematicians' understanding of squares with this geometry puzzle. The task is simple, identify as many squares as possible in a 3x3 array. Allow learners to work independently or in pairs as they search for squares,...
Curated OER
Place Value & Picasso
Place value to the millions is the focus of this math lesson. Third and fourth graders investigate multiple ways to represent a number. They examine place value while studying factual information about Pablo Picasso. Resources are provided.
Curated OER
Playing the Cards of Place Value
Third graders explore place value to the ten-thousands place. In this amazing, 21-page place value lesson, learners represent numbers in standard and expanded form, and use technology to represent numbers to 9,999.
Pennsylvania Department of Education
Thinking About Numbers from 1 to 20
Help your kindergarteners discover new number-sense concepts and to compose and decompose numbers. Though the resource contains no procedural details, the assessment tool (which you can find in the "printer friendly version") has lots of...
Pennsylvania Department of Education
Numbers Are Made of Parts
Children play with barnyard animal cards to practice composing and decomposing numbers. With their "secret number" of animal cards in a cup, they shake and spill them onto a barn story board, counting how many animals fall in the barn...
Curated OER
Finding the Area of Polygons
Third graders are exposed to finding the area of polygons by decomposing figures and recomposing them into rectangles. This strategy allows children to expand on their prior knowledge of constructing shapes by rearranging parts into...
Curated OER
Building Soil Nature's Way: Exploring decomposition and soil health
Students explore decomposition and soil health by creating their own garden. In this agriculture lesson, students build a "lasagna garden" with organic matter found in the area and plant perennials native to their region. Students are...
K20 LEARN
Building Numbers: Addition And Subtraction Up To 10
Animals on Board! Stuart J. Murphy introduces scholars to composed numbers in preparation for writing and drawing true or false number sentences. A game of Bear in the Cave challenges pupils to locate a missing addend. Sorting number...