Estimating the Sum of Given Numbers

We need estimation, when we don’t want an exact answer. Estimation is a fare guess of the sum and is close to the actual answer reasonably. 

For example; Robin has 37 white marbles and 83 red marbles. About how many marbles Robin has? 

To answer the above question we don't need to actually add the given numbers but need to give a good estimation of the sum of the numbers. The best approach to estimating sums is to round to nearest tens, hundreds or thousands. 

As the given numbers are less than one hundred we can round them to nearest tens as shown below: 

37 rounded to closest tens = 40 

83 rounded to closest tens = 80 

And 40 + 80 = 120 (we just add tens in our mind i.e. 4 tens + 8 tens = 12 tens = 120) 

So, Robin has about 120 marbles all together. 

Problem 2: Steve had $785 in his account before he deposited another $518 to his account. Find the approximate balance in Steve's account after the deposit? 

Solution: We need to round both the numbers to nearest hundreds in this case and then add the results: 

785 rounded to nearest hundreds = 800 

518 rounded to nearest hundreds = 500 

Estimated sum = 800 + 500 = 1 300 

Hence, Steve had approximately $1 300 in his bank account after the deposit. 

If 3rd grade students get able to estimate numbers to hundreds, this is a very good basic math achievement in arithmetic. But we can encourage them to do better than that. 

Below are the two worksheets to practice and get comfortable with estimating sums for  3rd grade math level;

PDF Link To Above Worksheet

PDF Link To Above Worksheet

 

Below is the link to 2nd grade math page, where you can print all the content for 2nd grade math

2ND GRADE MATH CORE CURRICULUM

Below are the links to my previous posts on 3rd grade math;

https://steemit.com/steemiteducation/@mathworksheets/3rd-grade-math-place-value-to-ten-thousands-lesson-and-worksheets-1  

https://steemit.com/steemiteducation/@mathworksheets/3rd-grade-math-place-value-to-ten-thousands-worksheets-2  

https://steemit.com/steemiteducation/@mathworksheets/3rd-grade-math-writing-numbers-to-ten-thousands-using-different-methods  

https://steemit.com/steemiteducation/@mathworksheets/3rd-grade-math-value-and-place-value-of-a-digit-in-a-given-number-1  

https://steemit.com/steemiteducation/@mathworksheets/3rd-grade-math-value-and-place-value-of-a-digit-in-a-number-2  

https://steemit.com/steemiteducation/@mathworksheets/3rd-grade-math-writing-place-value-of-an-underlined-digit-in-a-number  

https://steemit.com/steemiteducation/@mathworksheets/3rd-grade-math-value-of-an-underline-digit-in-a-number-worksheets  

https://steemit.com/steemiteducation/@mathworksheets/3rd-grade-math-worksheets-on-estimating-numbers  

https://steemit.com/steemiteducation/@mathworksheets/3rd-grade-math-comparing-and-ordering-numbers-1  

https://steemit.com/steemiteducation/@mathworksheets/3rd-grade-math-comparing-numbers-worksheets  

https://steemit.com/steemiteducation/@mathworksheets/3rd-grade-math-finding-greater-and-smaller-numbers-in-a-set-of-numbers 

https://steemit.com/steemiteducation/@mathworksheets/3rd-grade-math-finding-greater-and-smaller-number  

https://steemit.com/steemiteducation/@mathworksheets/3rd-grade-math-ordering-numbers-worksheets 

https://steemit.com/steemiteducation/@mathworksheets/3rd-grade-math-rounding-numbers-to-nearest-ten 

https://steemit.com/steemiteducation/@mathworksheets/3rd-grade-math-rounding-numbers-to-nearest-hundred 

https://steemit.com/steemiteducation/@mathworksheets/3rd-grade-math-rounding-numbers-to-nearest-thousand  

https://steemit.com/steemiteducation/@mathworksheets/3rd-grade-math-rounding-numbers-to-nearest-ten-thousands-worksheets  

https://steemit.com/steemiteducation/@mathworksheets/3rd-grade-math-skip-counting-by-3-s-and-4-s-worksheets 

https://steemit.com/steemiteducation/@mathworksheets/3rd-grade-math-skip-counting-by-5s-worksheets 

https://steemit.com/steemiteducation/@mathworksheets/3rd-grade-math-skip-counting-by-10s-and-25s-worksheets 

https://steemit.com/steemiteducation/@mathworksheets/3rd-grade-math-skip-counting-by-50s-and-100s-worksheets  

https://steemit.com/steemiteducation/@mathworksheets/3rd-grade-math-math-addition-facts-for-zero-and-one  

https://steemit.com/steemiteducation/@mathworksheets/3rd-grade-math-math-addition-facts-for-numbers-2-3-and-4  

https://steemit.com/steemiteducation/@mathworksheets/3rd-grade-math-addition-facts-for-numbers-5-and-6 

https://steemit.com/steemiteducation/@mathworksheets/3rd-grade-math-addition-fact-families-or-related-facts 

https://steemit.com/steemiteducation/@mathworksheets/3rd-grade-math-simple-addition-strategy-of-adding-doubles 

https://steemit.com/steemiteducation/@mathworksheets/3rd-grade-math-simple-addition-strategies-doubles-plus-one-and-doubles-plus-two 

https://steemit.com/steemiteducation/@mathworksheets/3rd-grade-math-simple-addition-equations 

https://steemit.com/steemiteducation/@mathworksheets/3rd-grade-math-double-digit-addition-without-regrouping  

https://steemit.com/steemiteducation/@mathworksheets/3rd-grade-math-double-digit-addition-with-regrouping  

https://steemit.com/steemiteducation/@mathworksheets/3rd-grade-math-three-digit-addition-without-and-with-regrouping  

https://steemit.com/steemiteducation/@mathworksheets/3rd-grade-math-adding-two-4-digit-numbers  

https://steemit.com/steemiteducation/@mathworksheets/3rd-grade-math-adding-three-and-four-numbers-vertically  

https://steemit.com/steemiteducation/@mathworksheets/3rd-grade-math-adding-numbers-when-they-have-different-number-of-digits