morningcoffee Posted February 17, 2017 Share Posted February 17, 2017 Ds is doing math mammoth grade 3 and the concept of doing the operation in the parenthesis is explained. There are 6 questions that follow which are obviously designed to show that the presence of a parenthesis will affect the final answer (eg. 20 – 6 – 2 = ______; 20 – (6 – 2) = ______). Then the student is asked to write an expression to match each instruction: "First add 40 and 50, then subtract that sum from 120.†“First add 70 and 50, then subtract 90 from that sum.†Ds found this quite a leap. Should we go back to math mammoth grade two and see if this is introduced and practiced earlier? Quote Link to comment Share on other sites More sharing options...
maize Posted February 17, 2017 Share Posted February 17, 2017 (edited) I don't think parentheses are introduced sooner. Is the trouble with translating words into numerical symbols? Maybe you can walk him through that with a few. "First add 40 and 50--OK, let's put that in parentheses to show that we do it first: (40+50); Now it says we need to subtract that from 120 so let's write the 120 in front and then a subtraction sign: 120-(40+50)" Then solve. If the large numbers are making it feel difficult try substituting small numbers--so you end up with 12-(4+5) Edited February 17, 2017 by maize 3 Quote Link to comment Share on other sites More sharing options...
HomeAgain Posted February 17, 2017 Share Posted February 17, 2017 The same thing is introduced in MEP 3. DS had a series of problems that had all the numbers and signs in the same order, but parentheses put in at different points in each problem to show the difference. For word problems like you mentioned, we found it easier to work on a whiteboard first, then paper. It allows for him to translate the words better if all he has to do is wipe and rewrite as he processes the information. 1 Quote Link to comment Share on other sites More sharing options...
Syllieann Posted February 17, 2017 Share Posted February 17, 2017 I don't recall seeing it in grade two. It is covered again in grade 4 and used extensively to develop the steps for the multiplication algorithm. I wouldn't stress it in grade 3. If you get to grade 4 and it is still a struggle, you can break it down and add review at that point. Maybe just doing a simple problem each day at the beginning of math time would help. 2 Quote Link to comment Share on other sites More sharing options...
fourisenough Posted February 17, 2017 Share Posted February 17, 2017 It's def not in grade 2; we just finished it. 1 Quote Link to comment Share on other sites More sharing options...
morningcoffee Posted February 18, 2017 Author Share Posted February 18, 2017 (edited) I don't think parentheses are introduced sooner. Is the trouble with translating words into numerical symbols? Maybe you can walk him through that with a few. "First add 40 and 50--OK, let's put that in parentheses to show that we do it first: (40+50); Now it says we need to subtract that from 120 so let's write the 120 in front and then a subtraction sign: 120-(40+50)" Then solve. If the large numbers are making it feel difficult try substituting small numbers--so you end up with 12-(4+5) Yes, it was the word to number translation that was hard. I did walk him through it but your explanation is much better than what I managed :001_smile: Edited February 18, 2017 by morningcoffee 1 Quote Link to comment Share on other sites More sharing options...
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