Math at Home Part 2 – Subtraction
This week, I am posting the subtraction strategies from the UGDSB Home Tip Sheet.
An important thing to remember is to point out relationships between concepts or operations. Many of the subtraction strategies can be shown as “the opposite” or “undoing” the adding strategies.
For example – “Counting Back” is really the same as “Counting On”.
Removal or adding up in chunks, relates to the student’s understanding of place value as they use “decomposing numbers” see a number sentence like 54 – 21 as 50 – 20 and 4 minus 1 = 30 and 3 or 33 (gr. 4 expectation). Dominoes or playing cards are a great way to play with these concepts with one side being the tens and the other the ones.
To extend this and make it a little harder increase the number to include hundreds or thousands. Or in grade 5 and 6, start working on decimal numbers.
Happy subtracting!
http://www.edu.gov.on.ca/eng/curriculum/elementary/math18curr.pdf
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