I.E.S.
“Andrés
de
Vandelvira”
-
Sección
Europea
Mathematics
d)
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Calculate the unknown number in the following cases: a)
3 of a number is 27, so the number is: 8
b)
2 of a number is 64, so the number is: 3
c)
17 of a number is 629 so the number is: 22
d)
2 of a number is 360 so the number is: 17
9 Dividing fractions To divide fractions, multiply the first by the reciprocal of the second fraction. The reciprocal of a fraction is obtained by switching its numerator and denominator. We can also take the cross product. To divide a number by a fraction, multiply the number by the reciprocal of the fraction.
Example: 4 7 4 ⋅ 11 44 4 7 4 11 44 : = ⋅ = or simply taking the cross product : = = 5 11 5 7 35 5 11 5 ⋅ 7 35
Exercise 8
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