Percentage and Decimal Review - Online Tutor, Practice Problems & Exam Prep

Understanding the conversion between percentages and decimals is essential in mathematics. To convert a percentage to a decimal, move the decimal point two spaces to the left; for example, 50% becomes 0.50. Conversely, to convert a decimal to a percentage, move the decimal point two spaces to the right, such as 0.34 becoming 34%. Mastering these conversions aids in grasping concepts like demand, supply, and market equilibrium, which are foundational in economics. Recognizing the implications of these conversions enhances comprehension of economic principles and their applications in real-world scenarios.

Converting Percentages and Decimals

So now let's do a quick review of percentages and decimals. The first thing we want to be able to do is switch between percentages and decimals. Take a percentage and turn it into a decimal or a decimal and turn it into a percentage. In both cases, the idea is we have to identify where the decimal point is, and a lot of times that's easy if you have a number like 150.23, but what if you just had the number 16? In this situation, the decimal point is implied at the end. So that's the decimal point after the 16. If you don't see one, it's going to be at the end, and when we're going from percentage to decimal, we're going to move the decimal point 2 spaces to the left when we go from percentage to decimal and when we're going from decimal to percentage, we're going to also move 2 places here, but we're going to move to the right. Cool?

Alright. So let's go ahead and practice a little bit. I'm just going to keep this in the same video for this practice. So what I want you to do is, why don't you pause the video real quick and do these and then continue, and we'll go through them together. Alright. So I'm guessing you paused the video and you're back now. So let's do this. 50% and we're going to convert it to a decimal. So we start with this one. The decimal is implied after the 50, so we are going to move it 2 places to the left, and we are going to get a decimal of my answer's in blue 0.50. Alright, 0.50 or 0.5. You can drop that last 0 and it's okay.

Alright. Let's do this next one. 1.25%. Now we're going to move it 2 places to the left, and now our new decimals here, we have to add a 0 in there, and we are going to get 0.0125 for 1.25%. Let's try the same thing with a 120%. So we've got our decimal point right there. Move 2 to the left. We're going to get 1.2 is equal to 120%. Same thing for 5% over here. Our decimals here. So we're going to move it 1 space, 2 spaces, fill it with a 0, and we are going to get, 0.05 for that one.

So compare that one with 50%, the first one that we did. Right? You want to be able to see the difference between 5% and 50%. Notice we've got that point 05 there. How about this next one, 31.34? We're just going to move the decimal two to the left and get point 3134. 12.5%. 2 to the left. Point 125. So compare that with the 1.25% right above it, and here we have 0.5%. So notice comparing this to 5% and 50%. So we're going to move it 1, 2 spaces, add a 0 in there, and we're going to get 0.005 is 0.5%. Alright? And a 100%, last one here. Move it 2, and we're going to get 1, just 1.

Let's do the same thing here with the decimals to percentage on the bottom. So pause the video real quick, try these out, and then let's do them together. Alright. So you're back now. Let's go ahead and solve these, decimals to percentage. So the first one here, 0.34, we're going to move 2 to the right to become a percentage. We're going to get 34% for this first one. How about 0.61? Same thing. Move 2. You're going to get 61%. Let me move out of the way here. 0.06. Move 2, and we are going to get 6%. 0.4512, we'll move 2, and we'll get 45.12%. Right. How about 0.0004? We're going to also, same process, move it over 2 and we are going to get a decimal of 0.04. You could also write 0.04, right, and that is a percent. Right. 0.04%. The last one here, the number 1. Remember if it doesn't give us the decimal, it's implied at the end. So we're going to move it 1, 2, add the zeros, and we'll get 100% for 1. Cool. So that is converting percentages and decimals. Let's move on to the next video.

Here’s what students ask on this topic:

How do you convert a percentage to a decimal?

To convert a percentage to a decimal, you need to move the decimal point two spaces to the left. For example, if you have 50%, you move the decimal point two spaces to the left, resulting in 0.50. This is because percentages are essentially fractions out of 100, so moving the decimal point two places to the left divides the number by 100. Another example is 1.25%, which becomes 0.0125 when converted to a decimal.

How do you convert a decimal to a percentage?

To convert a decimal to a percentage, you need to move the decimal point two spaces to the right. For instance, if you have 0.34, you move the decimal point two spaces to the right, resulting in 34%. This is because moving the decimal point two places to the right multiplies the number by 100. Another example is 0.06, which becomes 6% when converted to a percentage.

What is the decimal equivalent of 120%?

To find the decimal equivalent of 120%, you move the decimal point two spaces to the left. Starting with 120%, you move the decimal point two spaces to the left, resulting in 1.2. This conversion is essential for understanding how percentages greater than 100% translate into decimal form, which can be useful in various mathematical and economic contexts.

What is the percentage equivalent of 0.4512?

To convert the decimal 0.4512 to a percentage, you move the decimal point two spaces to the right. This results in 45.12%. This conversion is important for interpreting data and understanding how decimals represent parts of a whole in percentage terms, which is frequently used in economic analysis and other fields.

How do you handle implied decimal points when converting between percentages and decimals?

When converting between percentages and decimals, if a number does not explicitly show a decimal point, it is implied to be at the end of the number. For example, the number 16 is treated as 16.0. When converting 16% to a decimal, you move the implied decimal point two spaces to the left, resulting in 0.16. Conversely, when converting the decimal 1 to a percentage, you move the implied decimal point two spaces to the right, resulting in 100%.