Rewriting fraction as a decimal to the hundredths place | Decimals | Pre-Algebra | Khan Academy

TL;DR

The video explains how to convert the fraction 21/60 to a decimal by simplifying it and moving the decimal point.

Transcript

Let's see if we can write 21/60 as a decimal. And I'll give you a little hint. See if you can rewrite this as a fraction with 100 as the denominator. Or another way to say it is see if you can rewrite this so it's a certain number of hundredths, and then you can represent that as a decimal. So we've done this before. We can rewrite a fraction. We c... Read More

Key Insights

• 🧑‍🏭 Converting a fraction to a decimal involves simplifying the fraction by dividing the numerator and denominator by their common factor.
• 💄 Simplifying fractions makes it easier to convert them to decimals by manipulating the denominator.
• ✊ To convert a fraction to a decimal, we can multiply both the numerator and denominator by the same number to make the denominator a power of 10.

Questions & Answers

Q: How can we convert 21/60 to a decimal?

To convert 21/60 to a decimal, we first need to simplify it by dividing both the numerator and denominator by their common factor, which is 3. This gives us 7/20.

Q: Why is it easier to convert 7/20 to a decimal?

It is easier to convert 7/20 to a decimal because the denominator (20) can be easily converted to 100 by multiplying it by 5. This allows us to represent the fraction as 35/100 or 35 hundredths.

Q: How can we represent 35/100 as a decimal?

To represent 35/100 as a decimal, we can move the decimal point two places to the left since the denominator has two zeros. This gives us 0.35 or 35 hundredths.

Q: Why is the decimal representation 0.35 and not 0.0035?

The decimal representation is 0.35 and not 0.0035 because 3/10 is equivalent to 30/100, which is 0.30 or 30 hundredths. When we add 5/100 to it, we get 35/100 or 0.35.

Summary & Key Takeaways

• The video demonstrates how to simplify the fraction 21/60 by dividing both the numerator and denominator by their common factor, 3.

• By simplifying, the fraction becomes 7/20, which makes it easier to convert to a decimal.

• To convert to a decimal, the numerator and denominator are multiplied by the same number (5 in this case) to make the denominator 100.