Rounding off and Estimation

Dear all,

Today's lesson concentrated on the teaching of rounding off of numbers up to a million and the use of the estimation mathematical symbol. Just to recap with you:

• There are two ways we can use to round off whole numbers to their nearest place value.
• In the first method, we circle the place value we want to round off to and underline the digit of the place value to the right of it. Then, we make use of this concept '5 - 9 round it up' and '0 to 4 round it down'.
• In the number 108923, if I want to round this number to the nearest thousand, I would circle the number 8 (in the thousands place) and underline the number 9 (the next place value to the right of the place value of thousands). Since 9 is rounding up, the '8' would have to round up to '9' and as such, the answer of 108923 when rounded off to the nearest thousands would be 109000. 
• So, we say that 108923 is approximately 109000. 

• In the other method, we can use the number line method. 
• 108000 ----------------|-------------------|----109000
•                                                       108500                108923
• Since 108923 is towards the right, we then round it up to 109000. 

So far, based on my markings, the topic of whole number has been fairly simple on the whole. Most of you are able to get the concepts and skills right. However, the biggest problem lies in your accuracy. Many of you are still careless and you do not read carefully. You tend to assume, especially when it comes to number patterns questions. Thus, do read carefully and always check back! 

Homework:

• Pages 15 - 18 (Leave out Qn 7 on page 18)

Note:

• As part of Enrichment, we will be using the assessment book as seen below. My promise to all of you is that we will doing as much as we can for the workbook. There are chapters in which I will have to complete all the questions with you. As part of enrichment as as the word goes, it is to challenge you greater and get you thinking. Also, to have higher order thinking and exposure to difficult questions would help you to improve your mathematics. We will look at ways to solve problem sums and to tackle them successfully. There will be Part A (Semester 1) and Part B (Semester 2) and both books will cost $19.20. Do let me know if there are any objections to getting the books. Hope everyone will be able to get them. 

Sincerely,

Mr Nelson Ong