• document and explain the calculator keying sequences used to perform calculations involving rational numbers
  
  

Do the following calculation with as few keystrokes as possible.
The calculation to be done is , which gives the answer 0.2660754.

• Devise one way of obtaining this answer on your calculator. Write down the keystrokes that you used, both digit and operation keys, and record the number of keystrokes.
• Now devise another method. Which method uses fewer keystrokes? Again, write down the keystrokes that you used, both digit and operation keys, and record the number of keystrokes used.
• Explain each keying sequence, and explain why one of the sequences uses fewer keystrokes.

Complete the following calculations with as few keystrokes as possible.

3.2 [2.1 + 3 (4.6) 4 6.9] -15.1 = -2.02

• solve problems, using rational numbers in meaningful contexts

*A swimming pool is filled by means of three pipes. The first pipe can fill the pool in eight hours, the second can fill it in 12 hours, and the third can fill it in 24 hours. When all three pipes are in use at the same time, how long does it take to fill the pool?

Using each of the digits from 1 to 5 only once, write the largest and smallest power possible.

What are the last two digits of 11¹⁰⁰? Explain how you arrived at your answer.

A culture of 100 bacteria doubles every half hour. The formula to determine the size of the population (P) after time is given by P = 100 (2ⁿ), where n is the number of half hours. If the bacteria reach toxic levels when the population is 1.0 x 10⁵, how long does it take before this population is considered toxic?