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Math help in Salem, OR.

06/10/2015
As we rely more on technology, it becomes easy to forget that human input is what makes technology work. A calculator will make math easier, but if you do not understand the operation the calculator is performing, you do not know if you are receiving the right result. Estimation can help by giving you an idea of the right answer without being exact. Here are some tips and tricks to make your estimates more accurate.

Front-End

Focus on the first digit in a problem because it will have the biggest impact on the result. Then you can make minor adjustments to the other digits to make the numbers easier to work with. 
Example: 6,178 + 8,714 = 
Add 6,000 and 8,000 to get 14,000. Then see that 178 + 714 is almost 1,000, so you can adjust your estimate up to 15,000. 

Count Your Zeros

Example: 206*430 =
Round to 200 and 400. Now you can multiply 2*4 to get 8, then take the two zeros from 200 and the two zeros from 400 for a total of four zeros. 80,000. Isn’t that easy?

Averages

When you have a large group of similar numbers to add, you can estimate the average and then multiply by how many numbers there are. 
Example: 235 + 284 + 240 + 295 + 215 + 272 =
We have a group of six numbers who average about 250, so 250*6 = 1,500

Grouping

Put numbers together that are easy to work with. Look for sets of 10s, 100s or 1,000s as in these two examples.
Example 1: 77 + 65 + 22 + 31 = 
We see that 77 and 22 are almost 100, and 65 and 31 are almost 100, so 200 is our estimate.Example 2: 51*14*20 =  
Take the 51*20 as almost 1,000 (because 5*2=10 plus the two zeros), then multiply by 14 to get an estimate of 14,000. 

Decimals and Fractions

When dealing with portions of whole numbers, think about what the portion means. Is it closer to 0, to 1, or to half?
Example 1: 2.4*40 =
Since 0.4 is close to half, we can multiply 40*2=80 then add half of 40 (20) and get an estimate of 100. Adjust down a bit because we rounded up and we get 98.  

Example 2: 9/10 + ⅞ =
Since both fractions are close to 1, we can estimate that the answer will be around 2.Remember that percentages are like decimals. 

Example 3: What is 20% of 50 =
Since 20%=0.20, or two tenths, we can calculate one tenth of 50=5, then multiply by 2 to get 10. 

If your child wants to brush up on her math skills, check out The Tutoring Center in Salem, OR. We offer one-to-one tutoring in math, reading, writing, and test preparation. Remember that you do not need to be struggling to benefit from a tutor. Call us at 971-600-3288 to schedule a free diagnostic assessment and don’t forget to ask about our summer sessions. Visit us online to find out more information about our academic programs.  

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