AN INVESTIGATION INTO BASE 10 GROUPINGS

DAY 9

Connecting Abacus Models with Base 10 Names

Key Mathematical Ideas

Connect models to base 10 names (ones, tens, hundreds, and thousands).
Match their thinking on the abacus strings with arithmetic descriptions.
Label their models to show their thinking.
Understand the role of digits in base 10 numerals.

This video can be used for the explicit instruction to help you guide children through the tasks.

The key skills and understandings that are highlighted in the video and which you should encourage children to explore as they work with the abacus strings are:

Learning how zero plays a fundamental role as a place holder in numerals.
Understanding how to model numbers which contain zero e.g., 0 tens.
Matching their thinking on the abacus strings with an arithmetic description.

Exploration

Find bead 1080 on the abacus string.
What do you think the digit "0"means in this number?

Share their creative thinking on our Mathematics Community Forum

Support

Provide a template for children to fill in, with columns for the group name, symbol, and arithmetic description. Then pose the questions below:

What happens when I count to the tenth bead? Give children a moment to discuss think about this question. Then ask, how would I write the symbolic numeral for ten using the place value chart?
What does the digit “1” represent in the numeral (10)?
Can you explain how we move between the two groups?

Once children are comfortable with making groups of ten, ask them to explain what would happen when they reach 10 lots of ten. Are they still able to use their rule?

Extension

Annotate your abacus string and show how you are using an algorithm to make sense of the Linear Abacus® model. Challenge children to use exponential notation in their arithmetic descriptions (e.g., 10² for hundreds).

Micro Writing Task

Complete day 9 of your journal. For parents and teachers this prompt encourages children to have write a clear summary of their findings over the last few days. They are reviewing their learning so that new and old knowledge becomes connected.