Estimation is the power of guessing. In mathematics, estimation is important for students in several purposes. It can save time during exams, to make calculations easy and predictable. It also helps to develop mental math strategies.
In this article, we will discuss about estimation, tips, and tricks to estimate along with solved examples.
What is Estimation?
Estimation is the assumption of a number that is close enough to the right answer. It is an approximate calculation rounding off to the nearest point to make the problems easier to calculate. The estimated value or the closest meaning of an estimation is similar to the actual value.
In most of the cases, the estimation is made by rounding off the numbers to their nearest value, so that we can get a quick and simple answer. There are many tips and tricks to make an estimation, which we will discuss below. We can apply these tricks and tips individually or together to get a better estimation.
Tips & Tricks to Find Estimation
Estimation in math is a useful skill, that saves our time and helps in solving complex calculations in a simple way. Here are some tips and tricks for making estimations in mathematics:
Break Down Complex Problems
If we get any complex calculation, we have to split it into simple forms.
- For multiplication: 460 × 17 can be split into (400 × 17) + (60 × 17).
- For addition: (660+298) , here 298 is close to 300, then we can estimate it as (660+300)=960
By this you can easily estimate the value of the required solution.
Round the Numbers Up or Down Before Calculation
Round numbers to the nearest convenient value can be used to simplify calculations.
- Example: (306 × 395), here 306 is near to 300 and 395 is near to 400, then the answer will be close to 300 × 400 = 120000.
Group the Numbers Together
If there are many numbers given in the question, then arrange them in such a way that it becomes easy estimate the answer.
- Example: (76+54+23+40) here (76+22) is close to 100 and (54+40) is also close to 100, then the answer of the equation must be close to 200.
First Digit Estimation
The first digit of every number is important. Concentrate on the first digit and adjust the number to reach near to the answer easily.
- Example: (2156 + 3908) can be estimated by (2000 + 4000)=6000
Estimate Percentages
When calculating percentages, round the numbers involved to make estimation quicker.
For example, to find 15% of 78, round 78 to 80 and estimate 10% of 80 = 8 and 5% of 80 = 4. Hence, estimate value of 15% of 78 will be 12.
Benchmarking
Use benchmark numbers like 10% = 1/10 or 25% = 1/4 to quickly estimate percentages and fractions. For instance, to find 30% of 50, estimate it as 3/10 of 50 , which is 15.
Practice Mental Math Strategies
Practicing mental math and using estimation can improve speed and accuracy. It also helps to save time during calculations. For students, practicing triplets, percentages, Squares, Cubes are very important for their learning.
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Solved Examples on Estimation
Example 1: Estimate 236 divided by 3?
Answer:
Estimate 236 as 240, the estimated answer will be (240÷3) = 80.
Example 2: Estimate the difference between 15.7 and 8.9.
Answer:
Let us take the nearest whole number of 15.7 is 16 and 8.9 is 9. Then the difference = (15-9)=6 , the estimated difference is 6.
Example 3: A parking garage has 4 levels, each level can house 119 cars. Estimate the numbers of cars parked there?
Answer:
Let us take the nearest whole number of 119 is 120. Now the number of cars are = (120 × 4)=480
Example 4: Calculate 206 × 398.
Answer:
206 to nearest 100 is 200 and 398 is near to 400, the calculation will be (200 × 400) = 80000
Practice Problems on Estimation
1. Round of the number 4498 to the nearest hundred.
2. Riya has 623 stickers. She 97 stickers to her brother. Estimate how many stickers she has?
3. Estimate the sum of 25.29 and 29.8.
4. Which number is obtained when we round off 57.26 to the nearest whole numbers?
5. The moon takes 27.322 days to complete one earth rotation. Which is the nearest estimation?