Lesson video

Hi, I'm Mrs. Wheelhouse and welcome to our series of lessons on how to use your Casio calculator.

In these lessons, we're looking at three of the Casio calculator models, so let's get started.

By then, today's lesson, you are going to be able to use the fx-83 or 85GT CW to perform calculations with numbers.

Now these are some keywords we're gonna be using today.

You should be familiar with them, but if you're not, feel free to pause the video now while you read through the definitions on the screen.

Our lesson is broken into two parts.

We're going to begin by looking at how to convert.

In this lesson, we're going to be using the Casio fx-83 or 85GT CW model.

We will cover how to use this calculator to carry out different calculations.

After switching the calculator on, you will see this screen.

You can use the arrow keys to navigate between the options.

For now, we're going to focus on Calculate.

Press the EXE or execute button.

Inputting a mixed number into the calculator and pressing EXE returns the same value but as an improper fraction.

Let's do a quick check.

What does inputting an improper fraction into the calculator and pressing the EXE button return? Pause the video and make your choice now.

Welcome back.

You should have said it returns the same improper fraction.

"So how can I change between improper fractions and mixed numbers?" Well, "You need to use the FORMAT button." When any improper fraction is displayed, you can change the format of the value by pressing the FORMAT button, and you can see where it is here on the screen.

The value can be displayed as a decimal, improper fraction, or mixed fraction.

Let's do a quick check.

Using your calculator, select the correct equivalent decimal form for 1,349 over 52.

Pause the video and do this now.

Welcome back.

You should of course have pixie.

"Now, is there more that my calculator can convert?" "Well, yes, there is.

You can also convert time." Let's see what we mean by that.

We can change 2 hours and 20 minutes into just hours.

Pressing the SHIFT button, followed by the + button allows us to write in the form hour, minute, and second.

And you can see that here.

Pressing the FORMAT key allows you to display the time in different ways.

So 2 hours and 20 minutes can be said to be 2.

3 recurring hours, 7/3 of an hour, which is also the same as 2 1/3 hours.

A value in hours can be converted into hours, minutes, and seconds.

Pressing the SHIFT button, followed by the + converts to the form hour, minute, and second.

So 7.

6 hours is 7 hours and 36 minutes with 0 seconds.

Let's do a quick check.

3.

875 hours is equivalent to what time? Pause the video while use your calculator to work this out now.

Welcome back.

You should have said that it's equivalent to 3 hours, 52 minutes and 30 seconds.

Numbers can be written in prime factor form.

For example, 49 can be expressed as 7 squared and 124 can be expressed as 2 squared multiplied by 31.

Let's express 360 in prime factor form.

While we enter that number into the calculator and then press the Execute button.

We can then press FORMAT and select Prime Factor.

Press Execute.

Now gives that number in prime factor form.

So 360 is equivalent to 2 cubed multiplied by 3 squared, multiplied by 5.

Let's do a quick check.

Select the missing number, please.

So when I express 10,375,750 in prime factor form, it's 2 multiplied by 5 cubed, multiplied by 7, what, multiplied by 11 squared.

Pause the video while you work this out now.

Welcome back.

The missing exponent was 3.

Well done if you got that.

It's now time for our first task.

For question one, I'd like you to convert the following times to hours, please.

Pause the video while you do this now.

Welcome back.

Time for question two.

For question two, I'd like you to convert the following number of hours to hours, minutes and seconds.

Pause the video while you do this now.

Finally, question three.

Pause the video while you work this out now.

Time to go through our answers.

1 hour and 15 minutes is 1.

25 hours.

2 hours, 20 minutes and 20 seconds is 2.

338 recurring hours.

And 4 hours, 15 minutes and 16 seconds is 4.

254 recurring hours.

Well done if you've got those all right.

Question two.

7.

25 hours is 7 hours and 15 minutes.

3.

7 hours is 3 hours and 42 minutes.

7.

42 hours is 7 hours, 25 minutes and 12 seconds.

And 3.

63 hours is 3 hours, 37 minutes and 48 seconds.

Well done if you got that right.

Question three, you had to fill in the gaps.

So for a, you should have filled in the gap with the number 11.

For b, we had a missing exponent of 2 and a missing base of 5.

In c, we were missing 2 to the power of 7 and 3 to the power of 1.

And you could, of course, have written those in the other order if you wanted.

So 3 to the power of 1, multiplied by 2 to the power of 7.

And then in d, well, we needed to have 3 as the exponent to go with the base of 3, but for the question marks, now the values represented there have to be equal to 1.

So you could have a base of 1 and any exponent.

So for example, 1 to the power of a million would've been allowed.

Or you can have any base, but you must have an exponent of 0.

So you had options there.

Well done if you got that right.

It's now time for the second part of our lesson.

We're going to look at the lowest common multiple and highest common factor.

Now, as she points out, "That's some pretty useful stuff we've learned to do with our calculator, but what else can it do?" Well, "It can find the LCM or HCF for two positive integers.

Let's find the lowest common multiple of 4 and 6.

You need to press the Catalogue button, looks a little bit like an open book and then navigate to Numeric Calc.

Press the Execute button to see the options.

Navigate to LCM and press Execute.

You now enter the two values that you want to find the lowest common multiple of, use a comma to separate the values.

You can find that comma by pressing the SHIFT button and then the right parenthesis button.

When you are ready, press Execute.

The lowest common multiple of 4 and 6 is 12.

Let's do a quick check.

True or false? This particular model lets you find the lowest common multiple of three or more positive integers.

Is that true or is it false? And don't forget to justify your answer.

Pause the video while you do this now.

Welcome back.

You should have said it's false.

You can find the LCM for two positive integers.

Now, Aisha points out, "You said it can find the HCF as well, but I didn't see that option listed." And Sam says, "Ah, you are right.

Highest common factor is referred to as GCD on this calculator.

So if I want to find the highest common factor of 12 and 28, similar start, I press the Catalogue button and I navigate to Numeric Calc and then press Execute.

This time, I want to make sure that GCD is selected.

GCD stands for Greatest Common Divisor.

And it's another way to say highest common factor.

Now, we press Execute.

We enter the two values just like we did before, and we use a comma to separate those values.

When you're ready, you press the Execute button.

The highest common factor of 12 and 28 is 4.

Let's do a quick check.

Which option should be selected if we want to find the highest common factor? Is it GCD, LCM, or Round Off? Pause the video and make choice now.

Welcome back.

You should have picked option a.

It's now time for our final task.

On the next slide is a cross number.

Use the clues, and your calculator, to complete the cross number.

When you have finished, enter the numbers, left to right, from the shaded squares into your calculator and turn it upside down.

Write down the name you have found.

Good luck.

Pause the video now and have a go.

Welcome back.

Let's see what you should have put.

So when filling in your cross number, you should have got these values.

The name you would've gotten is Bill.

7718.

When turned upside down, looks like B-I-L-L.

Pause the video while you check your answers against what's on the screen.

Well done.

It's time start, we've looked at today.

This particular model, the fx-83/85GT CW can perform basic calculations and more.

It can convert between different formats for values.

And it can quickly calculate the LCM or HCF for a pair of positive integers.

Well done.

You've worked really well today and I hope you've enjoyed learning how to use some of the different functions of your calculator.

I look forward to seeing you for more maths in the future.

Goodbye for now.