ShmoopTube

Where Monty Python meets your 10th grade teacher.

Search Thousands of Shmoop Videos

CAHSEE Math 3.1 Mathematical Reasoning 176 Views


Share It!


Description:

Mathematical Reasoning Drill 3 Problem 1. Which of the following is the best estimate of [3.05(7.95) - 4] 2 ?

Language:
English Language

Transcript

00:02

And here's a shmoopy question for your brain.

00:05

Which of the following is the best estimate of 3.05 times 7.95 minus 4… squared?

00:12

And here are the potential answers…

00:17

So, where do we start?

00:19

The first thing we notice is that the problem asks us for an estimate, not an exact answer.

00:24

So, we don’t have to multiply 3.05 by 7.95…

00:29

…we just have to find something close to that product.

00:32

To do that, we can use rounding.

00:35

Turns out, 3.05 is pretty close to 3, and 7.95 is pretty close to 8.

00:42

So instead of the quantity 3.05 times 7.95 minus 4 squared...

00:47

…we have the quantity 3 times 8 minus 4 squared, which is a lot simpler.

00:51

To get our answer, all we have to do is multiply everything out, following PEMDAS.

00:56

We do everything inside the square parentheses first,

00:59

and multiply 3 and 8 before subtracting 4.

01:03

3 times 8 is 24, and 24 minus 4 is 20.

01:06

Then we square that, giving us 20 squared equals 400.

01:11

The answer is B.

Up Next

CAHSEE Math 5.3 Algebra and Functions
2032 Views

CAHSEE Math: Algebra and Functions Drill 5, Problem 3. Solve the equation.

Related Videos

Simplifying Radicals
9737 Views

We don't like knocking people down to size, but we do like simplifying radicals. Join us?

Arithmetic Math
2248 Views

If fleeing criminals always fled the scene of the crime at perfect right angles, it would be much easier to determine their whereabouts. Fortunatel...

Basics of Game Theory
882 Views

Okay, so this probably isn't going to help you master Pokemon Go, but game theory can be applied to all sorts of situations. Even stomping your old...