Understanding How to Express 0.85 as a Fraction

When you're staring down a number like 0.85, it’s easy to feel a little lost in the math maze. But don’t worry! Understanding how to express decimals as fractions is one of those foundational skills that'll serve you well in your math journey, especially when preparing for the Ontario Mathematics Proficiency Test. So, how do we take 0.85 and convert it into a fraction? Let’s break it down step-by-step.

First up, you need to recognize that 0.85 is actually 85 hundredths. This means we can represent it as a fraction: 85/100. Seems simple, right? Now, sharing numbers can be as easy as math pie (which, coincidentally, is a pretty great topic too). But just like a good pie, sometimes less is more—and we should simplify our fraction here.

To simplify 85/100, we need to find the greatest common divisor (GCD) of the numerator (85) and the denominator (100). You know what? This number is 5—it's like the magic number that’ll help us out. When we divide both the top (number on the top of the fraction, or numerator) and bottom (the denominator) by 5, we get:

• 85 ÷ 5 = 17
• 100 ÷ 5 = 20

Voila! We have simplified 85/100 down to 17/20. Therefore, the fraction that represents 0.85 is 17/20—and that’s how it matches one of the options you might find in a test setting.

Now, you might come across other choices, like 15/20, 8/10, and 7/8 in your learning adventures. It’s crucial to remember that while they look tempting, they don’t play nice with 0.85. For example:

• 15/20 simplifies to 3/4, which is 0.75, a bit shy of 0.85.
• 8/10 is the same as 4/5, or 0.8—it’s close but no cigar.
• 7/8 is around 0.875, which is a little more than 0.85.

So, whenever you see decimal numbers, remember this little trick: convert to a fraction first, simplify, and see how it fits. Easy peasy! If you need a little extra practice, try working on other decimals or reach out for more help—maybe check with your peers or grab a study group.

As you prepare for the Ontario Mathematics Proficiency Test, knowing these conversion tricks and simplifications can help you tackle those questions with strength. Each practice problem you solve builds confidence, and before you know it, you’ll be flying through those math challenges!