Finding The Increase Or Decrease Per Cent
Chapter Name : Comparing Quantities |
Sub Topic Code : 104_08_08_02_01 |
Topic Name : Finding The Increase Or Decrease Per Cent |
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Sub Topic Name : Finding The Increase Or Decrease Per Cent |
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Introduction
How is percentage calculated?
Pre-Requisites:
Basic knowledge about ratios and percentages
Activity:
The initial count of the number of sticks is used as 100. The percentage of extra sticks is found by comparing the number of extra sticks to the initial count and then multiplying it with 100. Same process is used to find the percentage of remaining sticks.
Real Life Question:
What is the quantity of a piece of pizza cut into 4 parts?
Key Words / FlashCards
| Key Words | Definitions (pref. in our own words) |
|---|---|
| Percentage | Term used to relate one quantity with the total quantity. |
Learning aids / Gadgets
| Gadgets | How it can be used |
|---|---|
| Ice cream sticks | Share a fixed number of ice cream sticks to all the students. Ask them to count them. Now add a few sticks and find the percent of extra sticks compared to initial count. Deduct a few sticks and find the percent of remaining sticks compared to initial count. |
Real life uses :
Maps, blue prints, medicine dosages, economic predictions, gear constructions, scaling
Practical examples around us
| Examples | Explainations |
|---|---|
| Maps | The maps are drawn by assuming a scale and building the map in proportionate ratios. |
| Medicine dosage | The dosage depends on the body weight of the person and various proportions of medicine is administered depending on weight. |
What you learn in Theory:
percentage is used to show ratio of a particular quantity with the whole quantity in fractions of 100. The percent of added quantities is found out in comparison with initial count. Similarly the percent of deducted quantities are also found.
What you learn in Practice:
The percent of extra sticks added is found by calculating the ratio of number of extra sticks to the existing sticks. This ratio is multiplied by 100 to get the percentage. Similarly the percentage of deducted sticks is found out.