SOLs Covered: 7.PFA.2 Expressions
Math Topic: 05 Simplifying Expressions
Daily Agenda: October 26-30, 2026
Upcoming Assessments: Unit 3 Expressions & Equations (Tues. 11/17)
Important Note: Friday, October 30 is a 3-Hour early release; Student holiday Mon. 11/2 & Tues. 11/3
Want to support the class? Here's our class store wishlist.
Greetings! This week's update is coming out a day early as I am out tomorrow for appointments. Before jumping into this week's math happenings, I realized I forgot to thank the Montano for their generous donation to the class "store" (the seaweed snacks are in high demand, so HUGE thank you!) as well as a mystery donor who bought Oreos off the Amazon wishlist (no name was included on the packing slip, so thank you, whoever you are!).
This week we tackled algebraic substitution. I started by showing students the "old school" way of writing it all out and working it out manually, step by step with a few extra components of my own. I require students rewrite the entire expression wherever the work is being complete to ensure they don't leave out part, specifically signs as that's a common mistake students make. To further help with this, we highlight each variable in different colors and put parentheses around them prior to substituting their values. Again, this is primarily due to students dropping signs, mostly negatives, when they go to replace the variables. They were told to also highlight the replacement values as SOL-type questions tend to throw little tricks into the problem by shuffling the replacement values in the directions in a different order than what is in the expression. From that point, students are just following the order of operations to finish evaluating.
We did several problems this way before I showed them the "new school" tech way using the Desmos calculator, which can handle substitution on it's own. Students always immediately start complaining about me making them do the other way, but as I explained to them, they need both methods for several reasons. First, they need to understand what is happening when they plug it into the calculator as some questions will ask for justification while others will ask you to find where a mistake was made. Second, one method can be used to check the answer for the other. Students don't immediately understand the importance of this until I show how a tiny change in the way something is typed into the calculator can result in a completely different answer and if they don't understand how the parts all work together, they won't spot the mistake. As I've mentioned before, SOL questions sometimes deliberately put tricks in them and the creators know the common mistakes students make and include those wrong answers as choices. Finally, there are some quirks to the Desmos calculator and if students forget about these and the tricks I've shared to counter those quirks or use different calculators, they will need the "old school" way in order to solve.
Students have done really well with this and it's showing in the quiz scores for those who have already finished. Everything we've done in topic 5 will help when we move onto the next few topics as students will need these skills to check all of their future algebra work, both this year and in the future. Students will be able to finish the quiz tomorrow or even next Wednesday as we'll be doing a term reset to get organized and prepared to start the next marking period off strong. We'll be cleaning out notebooks and backpacks of old math papers, saving those they can use for review later in the year when we start preparing for the SOLs.
That should cover everything but as always, please reach out if you have any questions. Again, I will be out tomorrow, but I'll respond to any emails between conferences on Monday or between meetings/planning on Tuesday. I hope everyone has an amazing weekend!