Better means to teach and assess

[Kalyan Ram]

Hi,

I am currently teaching 7th Maths at Kishkindapalem. I am currently employing the following techniques:

1. Provide notes on PPT essentially to ease the student to take notes and visual aimations help develop intuition for Math.

2. Use the whiteboard s/w for hands on sessions for Problem solving through screen sharing.

3. Mail assignments to class assistant when I think I have covered a topic.

The problem I face is the following:

The students some times are very perceptive and move couple of steps ahead in solving a problem, then when the exercises get slightly different are lost and fail to trace back. Here is an example as to how I explained the concept of addition and subtraction of integers

        Step 1) Explain the integers on the number line to get a feel for numbers and their ascending and descending order.

        Step 2) Introduce addition and subtraction of integers using number line. Direction change to be observed with positive and negative numbers. Then show it is good way to visualize but could be cumbersome when dealing with manipulating larger numbers.

        Step 3) Introduce negative integers as a result of subtracting larger number from a smaller number.

        Step 4) Then gave them a table to deal with sign manipulation in BODMAS situation.

When I introduced the closure, commutative,associative laws in addition and dealt with just positive numbers they were OK in fact doing it with ease, they were fine until here. Now the trouble begins when there is a combination of positive and negative numbers, I give them an example for verifying commutative law in addition say -15 + 23 the bright ones in the class come up with 23 - 15=8. I say its correct, but you cannot use Commutative law when verifying the Commutative law they are slightly confused but took my word for it. Then I say, use the OF operation in BODMAS rule to come up with -(15 - 23). Then observe that this will result in a negative integer as in the examples we have already dealt in Step 3, so we have -(-8) = 8. At this point I get questions like why is (- x - = +) but adding a positive and negative number not always resulting in negative number. I say this can be traced back to example like the ones we saw in Step 2, where we saw addition and subtraction are merely change of direction when operating with numbers on the number line, but none of this helps. They are completely lost and not able to trace back the steps.

I have a feeling that may be my approach is having a detrimental effect than proving beneficial. I would like to hear any suggestions to improve this situation any comments from teachers who experienced a similar situation or from colleagues who have a much simpler approach in such cases is much appreciated. I am open to discussion in the math-teachers forum or in case if someone want to have a Skype chat.

Regards,

~K.

[Meenakshi Ashokkumar]

Hi Kalyan,

Yes, the negative number operations are tricky especially when it comes to multiplication and division. Please go through the below link

https://www.mathsisfun.com/multiplying-negatives.html . There is a story which explains why two negative numbers on multiplication gives a positive number.This might help you.

However after the kids understand this concept,I think the rules should definitely be memorised like any other theorems or definitions in science.

We can also remind about the rules for negative number addition, subtraction , multiplication and division before every class for five minutes with examples till we gain the confidence that the children are clear.

Do let me know if these will be useful.

Thanks,

Meenakshi.

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[Sundaram Srinivasan]

----- Forwarded Message -----
From: Sundaram Srinivasan <sunil...@yahoo.com>
To: Kalyan Ram <kalya...@gmail.com>
Sent: Thursday, 17 September 2015 2:30 PM
Subject: Re: Better means to teach and assess

Hi

I am attaching a word file "Why negative of negative is positive". You may find it useful.

Regards

V S Sundaram

---

From: Kalyan Ram <kalya...@gmail.com>
To: foru...@evidyaloka.org
Sent: Thursday, 17 September 2015 3:55 AM
Subject: Better means to teach and assess

[Kalyan Ram]

Thank you Vasudha, Meenakshi, Sudaram for you suggestions will

implement them.

Regards,

~K

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