Estimate Percents

Today's Goal: Today students will be able to round numbers including percents to estimate a percent of a number.

Notes

The easiest way to estimate a percent is to round both numbers to numbers that are easy to work with.

Then, use the bar chart method or the percent of a number method.

Bar Chart Method

What is 23% of 189 pets.

First round the numbers:

23 rounds to 20

189 rounds to 200.

Now use the bar charts.

Videos

Create the percent bar

Create the other (Pets in this case) bar

Here is a longer video going a little deeper.

Shade the section(s) needed.

I need one section in the percent bar to get 20%, so I need one section in the pets bar.

Practice Sties

Number Invaders - Tough game, it goes really fast. Start easy with 10% and move up if you are brave enough.

Percent Estimation - Use the 100 chart to estimate the precent of the figure that is red. Be sure to change the number of exercises to a number other than one or it makes for a really short game.

So 20% of 200 is about 40

Percent of a Number Method

What is 23% of 189 pets.

First round the numbers:

23 rounds to 20

189 rounds to 200.

Now use the percent of a number method.

Change the percent to a decimals and multiply.

23% becomes .23 so, .23 X 200

Now place the decimal in this case two places to the left making the answer: 46.00 or 46 pets.

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