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### Course: Arithmetic>Unit 12

Learn all about how to estimate when adding decimals. Practice rounding to the nearest whole number and how this can help us get a close approximation of the actual answer.

## Want to join the conversation?

• What is the difference between estimating and rounding.
• Estimating is finding the answer by rounding and rounding... well, rounding is just rounding
• but, from where u bring the 8
(1 vote)
• He doesn’t bring an 8
• i have a test tomorrow and it's about estmating decimal sums and diffrences,adding decimals using mental math,adding decimals by regrouping,exploring problems that invlove decimals, and subtracting decimals by renaming! idon't get any of that so how should i study??
• there is a pattern 19,10,9. like 10+9=19
• Yes, but does that have anything to do with quantum mechanics?
(1 vote)
• decimals are easy, who's with me
• what now? i dont even know! oof me
• In , you said that wrong. You were supposed to say: "Here were told five point 1.
• this is hard. why. someone please help me understand the back ground to this. any help.
• Hi ahm3021139
this is easy if you know how to round.
so 1.64 + 2.4 is equal to 4, if you take out the .04 part. that means you need to round it down to the nearest tenth to make it equal to 4. 1.64 + 2.4 is approximately equal to 4, because if you round to the nearest tenth, it's 1.6 + 2.4.
• 5.1 + 4.91 is actually 10.1
• Great Job, you were so close. Always remember, that after you line up your decimals, you can add a 0 at the end, because if you add a 0 after your decimal point, where your numbers stop, it will not change your value.
• Why round when you can estmate?
(1 vote)
• Rounding and estimating are related…

Both are tools used together to make an approximation of a complete calculation.

When we estimate we're trying to get close to the answer, without having to calculate it exactly, and we use rounding to make that happen.

The closer to the real answer we get, 'the better' that estimation is considered.

Which is why the video points out…

It's best if we round one number a little bit down, and round one number a little up because it helps balance out what is lost and gained through rounding, so the estimation will be closer to the real answer.

We should pay attention and be aware which way we round each value, so we will know if the estimate is 'on the high side', or the 'low side' of the exact answer.

That's what the video is about

How to use rounding thoughtfully to make accurate estimates.
(1 vote)