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Secondary 1 | Maths
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Question involving integer. Explanation greatly appreciated. Thanks for the help.
Date Posted: 3 years ago
Views: 217
Such a question is in the generalised form.
What you can do is to specialise and try it out with some numbers first. Then work towards the general case.
①
For example, let's say Ali keyed in 5 (a positive integer) into the computer program.
The avatar will move forward by 5 units.
Then, let's say Ali keyed in -3 (a negative integer) into the computer program.
The avatar will move backwards by -(-3) units = 3 units
Since distance is always positive as it is an absolute value, we have to describe the moving backwards with a positive number.
But -3 is a negative integer, so we have to put a - sign in front to make it a positive value.
What you can do is to specialise and try it out with some numbers first. Then work towards the general case.
①
For example, let's say Ali keyed in 5 (a positive integer) into the computer program.
The avatar will move forward by 5 units.
Then, let's say Ali keyed in -3 (a negative integer) into the computer program.
The avatar will move backwards by -(-3) units = 3 units
Since distance is always positive as it is an absolute value, we have to describe the moving backwards with a positive number.
But -3 is a negative integer, so we have to put a - sign in front to make it a positive value.
So total distance moved
= 5 units - (-3) units
= 5 units + 3 units
= 8 units
Example ② :
Let h = 4, k = -8
Distance moved forward = 4 units
Distance moved backward = -(-8) units = 8 units
Total distance moved
= 4 units - (-8) units
= 4 units + 8 units
= 12 units
Now for the general case it would be :
Total distance moved = h units - k units
= (h - k) units
= 5 units - (-3) units
= 5 units + 3 units
= 8 units
Example ② :
Let h = 4, k = -8
Distance moved forward = 4 units
Distance moved backward = -(-8) units = 8 units
Total distance moved
= 4 units - (-8) units
= 4 units + 8 units
= 12 units
Now for the general case it would be :
Total distance moved = h units - k units
= (h - k) units
See 1 Answer
This question tests your understanding of integers with positive and negative directions.
There is always a 'positive' direction. Let's take left and right as examples. If right is my positive direction, then left is my negative direction.
If I move +2 steps to the right, it is the same as taking -2 steps to the left. However, when calculating the distance I took, we will not say "minus 2 units" since distance has to be positive.
In your question, the avatar moved forward by h units (positive) and then moved backwards by -k units (positive). Total distance moved will simply then be (h-k) units.
There is always a 'positive' direction. Let's take left and right as examples. If right is my positive direction, then left is my negative direction.
If I move +2 steps to the right, it is the same as taking -2 steps to the left. However, when calculating the distance I took, we will not say "minus 2 units" since distance has to be positive.
In your question, the avatar moved forward by h units (positive) and then moved backwards by -k units (positive). Total distance moved will simply then be (h-k) units.
@Dumbfungus : if the question were 'how far is the avatar from its original position?' it would be (h + k) units instead.
Thanks for the help, explanation was great too.
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