By the end of the lesson the learner can share a quantity in a given ratio.
By the end of the lesson the learner can solve problems involving direct and inverse proportion.
By the end of the lesson the learner can calculate percentage increase, decrease and percentage of a quantity in everyday contexts.
Transcript
[0:00] A ratio compares two or more quantities of the same kind, such as the ratio of boys to girls in a class.
[0:40] To share in a ratio, add the parts, divide the total by that sum, then multiply by each part.
[1:25] In direct proportion, when one quantity grows the other grows in the same measure; price and quantity bought behave this way.
[2:05] In inverse proportion, when one quantity grows the other shrinks; more workers means fewer days for the same job.
[2:45] A percentage is simply a fraction out of one hundred, useful for discounts, profit and exam marks.
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