Multiplication & Division

Objectives

To quickly multiply by 10 and 100 and to see the connection between multiplication and division.

Resources

Abacus 4 Textbook 3 | Squared paper | How to multiply and divide numbers by 10, 100 and 1000 (YouTube)

Today's Lesson

Main Activity

For the mental warm ups, call out a few random 3 digit numbers and ask your student to add them mentally.

For example:

123 + 200 =

240 + 130 =

Turn to page 81 in Abacus 4 Textbook 3.

Remind your student how to multiply by 10, simply by moving all digits in the number one place value column to the left. When decimals are involved, the process is just as easy, again moving all digits in the number one column to the left, keeping the decimal point fixed in place.

For example:

0.2 x 10 = 2.0 or 2

In exactly the same way, when dividing by 10, the digits move one place to the right.

For example:

0.2 ÷ 10 = 0.02

When there is a 2 digit number, the division follows exactly the same principle.

For example:4.6

46 ÷ 10 =

Watch How to multiply and divide numbers by 10, 100 and 1000 (YouTube) to understand how this works using a place value chart.

Ask your student to copy and complete the calculations on the page.

Citations

[1] www.youtube.com