Estimating with Powers of Ten

Refresh on Rounding!

When rounding, look at the digit AFTER the place value you are rounding to. If that digit is 4 or less, "let it rest" (you don't change the value). If it is 5 or more "raise the score" (round up).

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Everything after turns to zero​

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Place Value​

You may be told to round to a nearest place value, so the following slide reminds you the names of each place value! Write it down in your notebook if you need to.​

​Rounding Less than 1

If you are rounding in a place value below the ones place (to the right of the decimal), it follows the same rules. However, anything after the digit you rounded to no longer needs to be there. You do not have to put zeros.

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For example: 0.345078 rounded to the nearest hundredth is just 0.35​

Examples:

A power of ten is the number 1 followed by the number of zeros equal to the given exponent.

If the exponent is negative, the zeros occur before the one, including a zero before the decimal place​

​Powers of Ten

Some text here about the topic of discussion

​Estimating with Powers of 10

You can estimate a really large or small number using powers of 10 in a few simple steps.

1. Round the number to the largest place value

2. Count the zeros in your rounded number (remember, if it's less than 1, count the zero before the decimal place too!)

3. Rewrite your number as the digit times 10 to the power of how many zeros you have (if your number is less than 1, your exponent is negative)

Use a single digit and power of t​en to estimate 6,829,321,946

​Example:

Use a single digit and power of t​en to estimate 0.00000064589

​Example:

​Your Turn!

​Estimate 79,842 using a single digit multiplied by a power of 10

Multiple Choice

Step 3: Rewrite!

• $$8\times10^4$$  

• $$80000\times10^4$$  

• $$7\times10^4$$  

• $$79\times10^3$$  

Multiple Choice

Use a single digit multiplied by a power of ten to estimate 0.00009254

• $$9\times10^5$$  

• $$9\times10^4$$  

• $$9\times10^{-5}$$  

• $$9\times10^{-4}$$  

Multiple Choice

Use a single digit multiplied by a power of ten to estimate 875,325,960

• $$9\times10^8$$  

• $$8\times10^8$$  

• $$9\times10^{-8}$$  

• $$87\times10^7$$