Subtraction

Objectives

To apply different methods for place value subtraction and to establish which method is most comfortable.

Resources

Abacus 4 Textbooks 1 & 2 | Scanner or copier | Squared paper | Expanded Subtraction Methods - recap (YouTube) | Compact Column Subtraction (YouTube)

Today's Lesson

Main Activity

Turn to page 88 in Abacus 4 Textbook 1.

Using the chunking method, ask your student to copy and complete the division calculations on the page as a mental warm up.

Turn to page 14 in Abacus 4 Textbook 2.

Ask your student to look at the example at the top of the page, recognizing the links between the ‘place value explicit’ expanded method and the compact method alongside. Notice for example how ‘13 tens’ is shown in the two different methods, but means the same thing.

Use Expanded Subtraction Methods - recap (YouTube) and Compact Column Subtraction (YouTube) to recap if needed.

Copy and complete the subtraction calculations on the page. Your student might benefit from doing several calculations using both methods, before switching to just using the compact method when they are ready.

Citations

[1] www.youtube.com [2] www.youtube.com [3] www.youtube.com [4] www.youtube.com