1.2 Getting to Know the Calculator
In the following activities, you’ll learn how to use the web calculator that is easily accessible through your computer.
The calculator can be accessed on the left-hand side bar
under Toolkit. You might need to scroll down the screen to find it!
Look for the calculator picture on the left-hand side bar. Clicking on the link will open the calculator. If you would like to move the calculator to one side of the screen away from the main text, you can do this by clicking on the calculator with the left mouse button and holding this down. You will then be able to move the calculator where you would like.
Note that if you click away from the calculator it may appear to disappear from your screen. Don’t worry, it’s still there—but will be hiding behind the main text!
We will not be using most of the buttons toward the bottom of the calculator yet. Everything you will need at first is in the upper half. Don’t worry about looking at all of the features. If you need a new button, you will be introduced to it through the text.
The calculator works like most handheld calculators, though you can enter numbers and calculations in two ways, either by clicking on the buttons on the calculator itself, or by typing in numbers and mathematical signs directly in the white entry window.
Let’s start with an easy calculation that you can check in your head to make sure the calculator is working properly.
First, use the calculator buttons to create the entries. Although you
are not typing on your keyboard, you still need to make sure your cursor is
positioned in the white window before you start. Watch the two screens at
the top of the calculator (one black and one white) as you click on the
following keys: 
.
The black screen shows the complete calculation with the answer. The white screen shows the calculation as you are doing it, and after you press the equals sign, it shows only the answer.
Once the calculation is complete, it needs to be cleared before the
next calculation can be performed. You clear a calculation by clicking on
the 
button. Do this now; your last calculation should
disappear.
Try the same calculation by entering it using your keyboard. Type the numbers and mathematical signs either on the main keyboard or, if you have one, on the number pad. Type 2 + 5, then hit the Enter key. The calculator should display the same calculation as before.
Note that the flashing cursor must be in the white calculator window
before you can begin typing. If you can’t see it, click in the window, or
click on .
Correcting Mistakes
Suppose you want to calculate 37 − 19, but you mistype and enter 37 − 29 by mistake. The easiest way to correct this is to use the left arrow key on your keyboard until the cursor is flashing after the number you want to correct, then hit the Backspace key on your keyboard and type in the correct number. You can of course also erase more with backspace and retype as needed.
An alternative way is to use the little left arrow on the right side of the white entry window. It works like the Backspace key on your keyboard. Typing errors can be corrected by clicking on it.
Try it! Type 37 − 29 and correct it to 37 − 19.
Arithmetic on the Calculator
Now you’re ready to do arithmetic on this calculator. You can use either the buttons on the calculator or the ones on your keyboard, or a combination of the two—whichever suits you best. You may find the following table helpful in finding the correct button or key. You may find it useful to copy this table into your math notebook if you are not familiar with some of the keyboard alternatives.
In this activity, you are doing several straightforward calculations to make sure that you can get the calculator to work properly. Check the answer in your head so that you know what the calculator should show. Remember to clear the screen after each calculation, before you enter each new calculation.
Activity: A Few Arithmetic Problems
- (a)
- (b)
- (c)
- (d)
Discussion
Watch the screens at the top of the calculator to make sure you are entering the calculation correctly, and correct any mistakes as you go along. Remember to clear the screen each time before you start the next calculation.
Answer
The calculator should look like this:
Activity: Making the Calculator Do the
Work
Now for some calculations that you can’t do in your head so easily; use the calculator to find the answer to these.
- (a)
- (b)
Remember that although large numbers are sometimes written with commas to make reading the number easier (7,094 for example), commas (or spaces) are not entered on the calculator.
Discussion
Don’t be distracted by the size or complexity of the numbers. Enter each one carefully watching the screen to make sure that it is correct.
Answer
(a) The calculator shows: | |
(b) Before you
click |  |
After pressing  , it looks like this: |
1.1.7 Puzzles and Real-World Math