Week of February 20-24

Monday, February 20 was the first Presidents' Day we've had off in several years. Normally, we're using the day to make up a lost snow day. This winter, however, has been so unusually mild that we don't have any days to make up.

We just started working on algebra (solving simple equations). The rules to remember are pretty simple. Always keep both sides of the equation in balance, and isolate the variable by doing exactly the same thing to both sides. (Just like working with the numerator and denominator of a fraction.)

Example:
To solve n - 15.3 = 78.26
1.) Isolate the "n" by adding 15.3 to both sides (n-15.3+15.3 = 78.26+15.3)
2.) n = 93.56

While arithmetic can be thought of as "front to back" thinking, algebra works "back to front."
An arithmetic problem would be: What is 15 + 9? Just work it front to back and get 24. On the other hand, an algebra approach would be to start with the answer 24 and ask, "What number can we add to 15 to end with 24?" This kind of question requires starting at the end (24) and subtracting 15 from that answer to find the missing part of the addition problem.

The Unit 6 Test will start Thursday with the first section of the test that involves arithmetical computations. (Order of operations, number sentences, and division with fractions). The algebra section (solving and creating simple equations, and inequalities) will be given next Monday.

Week of February 13 - 17

The math classes are diving headfirst into algebra this week. (After Acuity testing on Monday, that is.)

Monday - This will be the final Acuity test this year before ISTEP starts in March. Students should bring along a book to read in case they finish early. (No RTI groups today)

Tuesday - We'll be looking at problems based on a pan balance model to show how equations need to be balanced on both sides of an equation. Homework is page 233 in the Journal. (Again no RTI groups today to provide enough testing time for Mr. Bastin's classes)

Wednesday - More work on the pan balance model and on solving equations by maintaining balance across the equation. There will be a worksheet page for this evening's homework.

Thursday - Students will be working today on creating their own equations and solving them in a small group activity. No homework tonight. The Family Math Night is set for 6:30 - 7:30 at MIS. The math teachers will be offering twenty minute sessions on a variety of math topics. Stop by room 218 for my mini-lesson on an alternative method for solving long division problems.

Friday - Students are working on equivalent equations today and will, again, have a chance to create some equations for their group to solve. Unless we fall too far behind, there will be no weekend homework.

Multiplying and Dividing Signed Numbers

To help remember the rules for multiplying and dividing signed numbers, we went back to the story of Little Red Riding Hood.

When Grandma was thinking about her granddaughter coming for a visit, that was a good thing for a good person, and we thought of that as good. (positive and positive made a positive)

But when Mr. Big Bad Wolf broke into Grandma's house, stole her cap and nightgown, and threw her in the closet that was a bad thing happening to a good person, and that was bad. (negative and positive make a negative)

While the wolf was lying in Grandma's bed drooling while thinking about how delicious Red was going to be, that was a good thing for a bad character, and that was also bad. (positive and negative make a negative)

Finally, when Red was tougher than the Wolf imagined and was given the beating he well deserved, it showed a bad thing happening to a bad character, and we think of that as a good thing. (negative and negative make a positive.)
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In mathematical language - When multiplying or dividing signed numbers:
* If the signs are the same (+ and + or - and -), the answer will be positive;
* If the signs are different (+ and - or - and +), the answer will be negative.