8: Advanced Proportional - Multiplication and Division

 

There is a strip of lawn in the middle of Annie's drive which is 0.6m by 23.4m. Is a bag of seed that covers 14 square metres enough to sow it?


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Student: Twenty-four times point six equals fourteen point four square metres. That's point six of a metre too long. Point six times point six equals zero point three six, so the lawn is fourteen point zero four square metres. That's close enough that the bag will cover it.

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Students at the Advanced Proportional stage are learning to select from a repertoire of part-whole strategies to solve and estimate the answers to problems involving fractions, proportions, and ratios. These strategies are based on finding common factors and include strategies for the multiplication of decimals and the calculation of percentages.