Saturday, June 08, 2024

The Backdoor

To enter, if the front door's open, walk right in. If it’s not, go ‘round back. This common sense advice applies to the SAT/ACT math section, as well.

While “doing the math” should always be plan A, plan B is to use a strategy, a “backdoor” approach to selecting the right answer. If the math is easy, do the math! If not, use a strategy.

Following are two classic backdoor strategies for answering questions on multiple-choice math questions. Each of them takes practice to master, but the advantage gained is well worth the effort. 

Try the answers

Math problems are typically solved by working forward from given information to the answer. This approach is the only option on typical “fill in the blank” tests taken in school, and on the SAT and ACT, students are expected to employ the same approach. But on multiple-choice tests, students have another option: it might be better to work backwards, from the answers to the problem. If answer are all numerals, this a good strategy to consider. 

Here's how it works:

Pick an answer choice. Take that answer back into the question and see if it’s consistent with all the given information. If there’s any inconsistency, eliminate that one, and try another. Only the correct answer will work. 

This strategy works best when answer choices are all numerals.

[Note: Since answers are arranged numerically, starting your search in the middle of the list will enable faster elimination and likely save time.]

Make up numbers

If variables are confusing you, don’t use variables. Use simple, real numbers instead! Here's how it works:

Pick simple sample values for the unknowns (don’t use 1, 0, or any number already appearing in the question), and answer the question using those numbers. Plug the same values into the answers, and pick the one that gives you the same result.

This approach works best when solving algebra problems and you're tempted to write some kind of difficult equation and/or when the answers all contain variables.

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Copyright © 2006-present: Christopher R. Borland. All rights reserved.

Saturday, June 01, 2024

Best Local Stargazing and Dark Sky Sites

Nothing says applied mathematics like physics, and nothing says physics stars and cosmology.

Following is a list of best places in the SF Bay Area and around California to find dark, clear skies ideal for star gazing.

A good pair of 7x50mm binoculars makes stargazing even more amazing. Click here for a great deal on an excellent set for beginners.