Expressing one number as a fraction of another
I can express one number as a fraction of another.
- Year 7
Expressing one number as a fraction of another
I can express one number as a fraction of another.
Lesson details
Key learning points
- There exists a multiplier for any pair of values.
- The multiplier is more than just a scaling factor.
- The multiplier also expresses one number as a fraction of the other.
Keywords
Reciprocal - The reciprocal is the multiplicative inverse of any non-zero number. Any non-zero number multiplied by its reciprocal is equal to 1.
Terminating decimal - A terminating decimal is one that has a finite number of digits after the decimal point.. E.g. 92.2, 193.3894, non-example: $$1.\\dot9$$.
Common misconception
Only see the amount, not proportion. E.g £30 from £100 is no different to £30 from £60.
Referring to the whole using bar models or fractions can emphasise the amount with respect to the whole.
Equipment
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.Match the following to the correct reciprocal.
3 - $$1\over3$$
$$5\over2$$ - $$2\over5$$
1.25 - $$4\over5$$
$$5\over20$$ - 4
$$3 {1\over2}$$ - $$2\over7$$
Q2.A shop has a sale saving you $$1\over3$$. You pay £36 for a sweatshirt. How much was it originally?
Q3.$$1\over6$$ of 150 = $$5\over6$$ of .
Q4.I think of a number. $$5\over8$$ of my number is 15. What is my number?
Q5.The cost of a laptop increases by $$1\over8$$. It now costs £675. How much was it originally?
Q6.Alex's cat loses $$1\over7$$ of it's weight. It now weighs 4.2 kg, how heavy was it last year?
Assessment exit quiz
6 Questions
Q1.Which of the following are terminating decimals?
Q2.Match each calculation to the correct missing number.
6 × $$\square$$ = 4 - $$2\over3$$
6 × $$\square$$ = 10 - $$1 {{2} \over {3}}$$
$$\square$$ × 6 = $$3\over2$$ - $$1\over4$$
6 × $$\square$$ = 15 - 2.5
$$\square$$ × 6 = $$18\over7$$ - $$3\over7$$
Q3.A recipe requires 195 grams of chocolate chips to bake 30 cookies. What weight of chocolate chips would you need to make 130 cookies?
Q4.What fraction of 300 is 45? Give your answer in its simplest form.
Q5.If 30 is $$2\over3$$ of 45, which of the following is true?
Q6.Match the following with what needs to go in the box.
112 is $$\square$$ of 392 - $$2\over7$$
$$\square$$ of 445 is 178 - $$2\over5$$
261 is $$\square$$ of 609 - $$3\over7$$
$$\square$$ of 315 is 420 - $$4\over3$$
1524 is $$\square$$ of 2032 - $$3\over4$$
