This activity will help students better understand the idea of a missing factor in an equation.
Main Curriculum Tie:
Mathematics - 4th Grade
Standard 2 Objective 2
Use algebraic expressions, symbols, and properties of the operations to represent, simplify, and solve mathematical equations and inequalities.
- Rainbow cubes
- Recording sheet
- Adhesive dots
Background For Teachers:
Students should have a basic understanding of visual patterns and arrays. They
should be able to represent mathematical ideas with objects, pictures, and symbols.
Use this lesson to strengthen the idea of a missing factor in an equation. Students
also need to have a basic understanding of multiplication facts.
Intended Learning Outcomes:
2. Become mathematical problem solvers.
3. Reason mathematically.
4. Communicate mathematically.
5. Make mathematical connections.
Invitation to Learn
“We’ve been baking chocolate chip cookies and now we are ready to
display them on our trays. It is important that we display them in equal rows.
What are some different arrangements you can make on your tray?”
- Tell the students to make an arrangement of cookies (use the cubes as cookies)
on their recording sheets in equal rows.
- Ask volunteers to tell you about their arrangement. For example: “Three
rows of five muffins, fifteen muffins altogether.” Model how to write
a multiplication equation on the board that tells about the cookies on the
tray. Say, “Three times five equals fifteen.” Model how to write
the equation: 3 x 5 = 15.
- Repeat the above steps encouraging students to tell the multiplication
equation that describes their cookie picture. Continue until you have five
or six models on the board (make sure the students are making their models
on their work mats as you go along).
- Erase one factor in each equation you have listed on the board. Tell the
students that some frosting fell on the equation and covered some of the numbers.
- Ask students to help figure out what the missing numbers are. Some may
need to use the rainbow cubes, and others may be able to solve the problem
with their knowledge of math facts.
- Students should now use their recording sheets to write new equations that
tell about six different cooking arrangements
- Have students pass their equations to another student. This student spills
some frosting on one of the number equations by covering a number with an
adhesive dot. Continue passing around until all six equations have frosting
spilled on them.
- Return Recording Sheets to original student. Allow time to figure out the
missing numbers on their papers. They may again use the rainbow cubes to recreate
the picture or use their math facts to solve the problem.
Try writing an equation that they have to balance. For example: 2 + 10 = 3 x
__ The missing number has the frosting on it and they need to find the hidden
number to make the equation equal.
Evaluate the students’ recording sheets. Also have them record in their
Math Journals how they figured out what numbers were missing.
Created Date :
Aug 29 2003 08:59 AM