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Wordsworth Primary School

Wordsworth

Primary School

Estimating and using the Inverse 11.05.2020

Week beginning 11.05.2020

Good Morning Year 4 - Last week you all did incredibly well revisiting Rounding to the nearest 10,100 and 1000.

This week we will be revisiting Estimating.

Remember estimating isnt too dissimilar to rounding.  You are making an educated and sensible guess to an answer for example:

23 + 11 = I would using my rounding skills to round both the numbers down to the nearest 10 so I would estimate the answer to be 30.  The actual answer is 34.

If I bought a pencil for 25p and a rubber for 13p and a notepad for 89p = Using my rounding skills again I would round 25p up to 30p and 13p down to 10p and 89p up to 90p so I would estimate the answer to 130p or £1.30.  The actual answer is 127p or £1.27.

Watch this Mathsantics video to refresh your memory then have ago at Activity 1 Estimation.

https://www.youtube.com/watch?v=fd-E18EqSVk

Remember any questions to message your teacher or independently try and work it out - we have visited this before this year and in year 4 - so go on SMASH IT!

Watch BBC Bitesize

https://www.bbc.co.uk/bitesize/topics/zh8dmp3/articles/z874h39

Remember any questions to message your teacher or independently try and work it out - we have visited this before this year and in year 4 - so go on SMASH IT!

12.05.2020

Please find at the bottom of the page Activity 2 Estimation - You did really well with estimating the number of pencils - remember you are making a sensible guess using skills you already have.

Estimating the pencils - I counted how many at the top, roughly, then doubled it - giving me a sensible estimate of how many pencils there were. How did you do it?

13.05.2020

Please find attached at the bottom of the page Activity 3 Estimating and using the Inverse - remember the inverse is the opposite of the calculation you have already done and a way of checking to see if your answer is correct.

Top Tip - use a bar model to help you visually represent the inverse - I have modelled one on the activity sheet for you.

 

14.05.2020

Please find attached to the bottom of the page Activity 4 Estimating and Rounding - Today you are going to go shopping but you will be estimating whether you have enough money or not to buy the items by using your rounding skills.

Top Tip - Is £3000 enough money to buy

A Second hand Mini Car £1300 and a Motorbike £1215

1. I round the numbers to the nearest hundred

Mini car = £1300     Motorbike=£1200 

Add these together = £1300 + £1200 = £2500 (Rounded estimate) 

The answer is yes - £3000 would be enough money to buy a Mini and Motorbike.

15.05.2020

Year 4, this is the last day of Estimating and using the Inverse.  I have uploaded a final Digging Deeper Activity 5 at the bottom of the page.  Top Tip - Use all of what you have learnt this week - you have all done a SUPER job - Well done.