STEP
INTO THE GED
MATH PRACTICE: Introduction to the Scientific Calculator
RETURN TO: Scientific Calculator Passage
Note: Look at the instructions for the project in this unit. You will be working on both the math problems and your project at the same time.
Do the following two sets of math problems (Set A and Set B) in two ways. Work them out yourself by hand. Then find the answer by using your calculator.
Keep track of the time it takes you to do the problems both ways. Use the classroom clock if it has a second hand. Or buy a cheap stop watch.
Remember to follow the rule of operations: do the multiplication and division first; then do the addition and subtraction.
Click on the math icon to go to the Math Mentor for help with decimals.
Set A
1. 1.5 + .123 + 2.07 =
2. 637 − 50 =
3. 200 + 15 + 4 − 13 =
4. .13 + 3.6 + 44 + 61 =
5. 42 − 10 + 75 =
6. 16 × 10 =
7. 100 ÷ 4 + 6 =
8. 66 ÷ 11 =
9. 15 + 6 × 2 =
10. 47 × 8 ÷ 3 =
Set B
In order to do problems with fractions with a calculator, you will need to use one more key. Find the key that looks like this
a b/c
Note: It's on the left hand side under the shift button.
This is what you do. Problem: 3/8 + 1/8 = 4/8 Reduced to its lowest terms = 1/2
On the calculator, you would press these keys
press 3 press a b/c press 8
press + press 1 press a b/c
press 8 press =
=the result pops up.
The answer, ½ , will look like this on your calculator
1 _| 2
Now, do these problems.
Remember do them yourself by hand; then do them using the calculator. Keep a record of the time it takes to do each problem both ways.
Click on the math icon to go to the Math Mentor for help with fractions.
1. 1/2 + 1/2 =
2. 6/10 + 3/10 =
3. 1/4 + 1/2 =
4. 2/3 + 3/6 =
5. 3/4 − 1/8 =
6. 2/7 − 1/14 =
7. 1/2 − 1/3 =
8. 4/9 × 3/8 =
9. 9/10 × 4/5 =
10. 3/4 ÷ 1/2 =
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You can also do percent problems on the calculator. Remember that 50% is the same as .50. We will use decimals for percents here. In a later course, you will learn other ways of getting percentages.
50% = .50
Example:
Davis Construction Company made $50,000.00 this year. Of that amount, 75% represents the company’s costs. How much of the $50,000.00 is needed to cover costs?
When you know the percent and need to find the amount it represents, do this:
50000 × .75 = 37500 Answer: $37,500.00
When you know the amount and need to find the percent it represents, do this:
37500 ÷ 50000 = .75 Answer: 75%
Do the following percentage problems. Chose one of the methods above. (You do not need to keep track of time for these problems.)
Click on the math icon to go to the Math Mentor for help with percentages.
1. Joe’s Upholstery needs a profit of 11% to stay in business. The business made $60,000.00 last year. How much of that needs to be profit?
2. Salaries cost Johnson Tire Service $16,000.00 a month. In April, the business made $55,000.00. What percentage was spent on salaries?
3. Otis’ Boats and RV’s spent $6,000. 00 on security services. They made $40,000 for the month. What percentage goes to security services?
4. A history course in a college is based on 950 total points earned during the semester. John Adams wants to get at least a B in the course. What is 85% of 950?
5. Medical personnel would like people to limit the fat in their food to 30% of the daily calories eaten. If Mary eats 1850 calories a day, what number of those calories can come from fat?
6. The employees at Tasty Pizza spend 50 minutes out of an 8 hour day on coffee breaks and conversations. What percentage of their time is not being spent working?