Basic Operation and Decimals (Multiplication)

 

Lesson Planning of Basic Operation and Decimals (Multiplication)

Subject Mathematics

Grade 4^th

Students` Learning Outcomes

• The students will be able to multiply a decimal by 10, 100, and 1000.

Information for Teachers

• When multiplying by 10, 100, and 1000, etc. count the zeros to find out how much bigger your number must be.
• This is a multiplication skill and hence need drill. The more they exercise the more they understand.
• Since they have already done in tables like 2 times 10, 6 times 10 etc.
• Teacher should use/ consult from textbook where and when required.

Material / Resources

Writing board, chalk/marker, duster, paper and pencils for the whole class

Introduction

• Verbal math`s can you tell?
• 2 x 10?
• 4 x 100?
• 10 x 10?
• What are we doing?
• What are appending zeros, as per 10 or its power?
• Today we will observe multiplication of decimal values by 10, 100, and 1000.
• Do you know?
• There is a decimal point in every number!!!
• 5 is actually 5.0000…, 84 is actually 84.0000
• Just like every number these can also be written as a fraction 84 /1, 5/1 etc.
• So when we multiply these decimal jumps to right!
• Let`s see how!

Development

 

Activity 1 Present the given model to the class to multiply:as; 10 move the numbers 1 place to the left. 100 move the numbers 2 places to the left. 1000 move the numbers 3 places to the left. Write place values on board. Add zeros and explain verbally as mentioned above. Teacher`s input: There is a short cut method! When multiplying by 10, 100, and 1000 there`s a pattern that can help you get the right answer very quickly. This method moves the decimal point rather than the digits. Multiplying number Number of places to move the decimal point 1,0 1 1,00 2 1,000 3 10,000 4 Zeros in the multiplying number tell you how many places to move the decimal point. Example: Multiply 2.341 by 100. 100 have two zeros. Make 2.34 bigger by moving the decimal points to two place right, as; 5.641 x 100 = 564.1. Explain with few more examples.

 

Activity 2 Textbook activity Ask the students to solve practice pages given in their mathematics book. invite the students on the board to show movement of decimal to the right.

Sum up / Conclusion

• When multiplying by 10, 100, and 1000 etc. count the zeros to find out how much bigger your number must be.
• In this method the decimal point moves rather that the digit.

Assessment

• Complete the following table:

Solve:

Follow up

• Write questions to multiply with 10, 100, and 1000?
• Solve these questions by multiplying with 10.