From the course: Test Prep: SAT

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Estimation technique

Estimation technique

From the course: Test Prep: SAT

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Estimation technique

- One of the most valuable skills you can use on the SAT math sections is estimating. This video will give you a few ideas about how to use estimation to both come up with and confirm your answers. So whatever type of math you're doing on the SAT, it's almost always useful to have a logical idea of what your answer might look like before you actually do any math. So I'll give you an example with this question I just wrote. The sales tax in Arlandia is 8%. How much sales tax will you pay if you buy a car that costs $20,000? So, if you're trying to calculate this question before you start, you might say to yourself, well, I can get a rough estimate by taking 10% of 20,000 and going a little bit lower, because 10% is pretty close to 8%. So the first thing we would do is round 8% up to 10%. And then it's really easy to take 10% of a number. You just take the decimal point and move it one spot to the left. So if we do that to the number 20,000, it becomes 2,000. Since we're looking for 8%…

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