Subtraction

Objectives

To apply the preferred subtraction method

Resources

Abacus 4 Textbook 1 | Squared paper | Frog Method Subtraction (YouTube) | Subtraction by counting back (YouTube)

Today's Lesson

Main Activity

Ask your student to recite the last two times tables and answer questions on these. Your student should have recited all 12 times tables throughout the course of the week. New students should now be able to recite the 2, 3 & 4 times tables and to be able to answer random questions on these.

Turn to page 23 in Abacus 4 Textbook 1.

Watch the video which was introduced in the last lesson to recap the ‘counting up’ and ‘take away’ strategies for subtraction.

Look at the page with your student and point out the three digit numbers. If your student prefers the take away method we used in the last lesson, it is important to recognize that not of all the tens digits of the first of the three digit numbers are greater than the tens digits of the numbers being subtracted. This will have implications for the final answer. Therefore, suggest that the counting on (‘frog’) method be used for these calculations. Help your student to identify the numbers where this will be necessary.

Once your student is comfortable with choosing an appropriate method for subtraction, ask them to copy and complete the calculations.

Citations

[1] www.youtube.com [2] www.youtube.com