Converting decimals to percents example 2 | Decimals | Pre-Algebra | Khan Academy

Understanding how to convert a decimal to a percent comes in really handy sometimes. Let's practice using this problem.

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Vi skal skrive 1,501 som procent.

Tricket er at skrive 1,501 som en brøk som noget over 100.

Det vi kan gøre er at skrive det som 1,501 over 1 til at starte med.

En brøk med nævneren 1 er svarer til værdien af tælleren. Det kan vi nu gange med 100 over 100.

100 over 100 er det samme som 1,

så brøkens værdi er stadig den samme.

Men nu får vi en brøk med nævneren 100, og det var det, vi gerne ville.

Nævneren bliver som sagt 100 - 1 gange 100 er 100.

.

Vi skal også gange tælleren med 100, så vi skal også gange 1,501 med 100.

.

Hvis vi ganger den med 10,

flytter vi kommaet én plads til højre.

men vi skulle gange med 100,

så vi ganger med 10 igen.

Vi skal altså flytte kommaet 2 pladser til højre.

Det svarer til, at vi har ganget med 100 -

eller med 10 to gange.

.

.

Kommaet står altså nu mellem 0 og 1,

så svaret bliver 150,1.

Nu har vi omskrevet 1,501 til 150,1 over 100

eller 150,1 PER 100.

Så vi har 150,1 per 100,

eller 150,1 per cent.

Derfor bliver svaret 150,1%

Og så er vi færdige.

Det vi gjorde i bund og grund var,

at vi gangede de 1,501 med 100

- altså flyttede kommaet 2 pladser til højre -

og det tal vi fik - altså de 150,1 -

var vores procentsats.