Lesson plan
Doubling
Learning Objectives
Students will be able to double two-digit numbers.
Introduction
(5 minutes)- Hold up four objects, like pencils, and tell students that you need double the number of pencils you are holding. *Ask students how many pencils you’ll have if you double the number you are holding (eight).
- Hold up eight pencils and repeat the question.
- Hold up 16 pencils and repeat the question. (Note: at this point, students may have a more difficult time answering the question; provide the answer if students are stumped).
- Tell students that today we are going to be doubling numbers, just like I doubled the number of pencils I was holding. Doubling a number is multiplying it by two.
Explicit Instruction/Teacher modeling
(10 minutes)- On the board write 4 x 2 = 8 and explain, "When I was holding four pencils, and I doubled them, I had eight pencils."
- Repeat with 8 x 2 = 16 and 16 x 2 = 32.
- Tell students that doubling is a skill that can be useful in the real world, so today we are going to practice a strategy that will make it easy to think about doubles.
- Write 35 on the board.
- Explain that when we double a number, we can decompose, or break apart the number, and double each part. For example, 35 could be decomposed into 30 + 5.
- Point out that doubling the parts of the numbers (30 x 2) + (5 x 2) is easier to do in our heads than doubling the whole number.
- Tell students that 30 doubled is 60 and five doubled is 10. So 60 + 10 is the answer.
- On the board, write 60 + 10 = 70 / 35 x 2=70.
- Repeat with a second example, like 17.
Guided Practice
(15 minutes)- Write 23 on the board and have students work with a partner to double it, using decomposition as a strategy.
- Hand out the Double Bubbles worksheet.
- Have students complete the worksheet with a partner.
Independent working time
(10 minutes)- Hand out the Doubling in the Real World worksheet and instruct students to complete it independently.
- Circulate as students work and offer support as needed.
- Go over the worksheets as a class.
Differentiation
Support: Provide simplified practice problems with smaller numbers (i.e. 15, 21, 32).
Enrichment: Have students apply the strategies learned in the lesson to solve word problems.
Assessment
(5 minutes)- Hand out a sticky note to each student (or, alternatively, have students use personal white boards).
- Write a number on the board, like 48, and instruct students to double it and write their answer on the sticky note.
- Collect as an exit ticket and check for understanding (Note: if using white boards, have students hold up their answer and scan to check for understanding).
Review and closing
(10 minutes)- Ask, "What are some real world situations when you might need to double a number?"
- Discuss as a class (i.e. making a recipe twice as big; buying two identical items and calculating the cost).
Related learning resources
Doubling
Lesson plan
Doubling
...Point out that doubling the parts of the numbers (30 x 2) + (5 x 2) is easier to do in our heads than doubling the whole number....
5th grade
Math
Lesson plan
Doubling in the Real World
Worksheet
Doubling in the Real World
Teach your student to use doubling as a strategy to solve real world problems.
5th grade
Math
Worksheet
Double Bubbles
Worksheet
Double Bubbles
Familiarize kids with the idea of doubling the value of something. This bubble-themed worksheet gives your students practice with doubling two-digit numbers.
5th grade
Math
Worksheet
