In this class, we use computational thinking to solve a mathematical problem.
Class Activity – Finding the sum of a range of numbers
Complete the following task in your ICT notebook showing all working
Task: Without the aid of your classmates, find the sum of all whole numbers from 1 to 200 inclusive.
Discovery: at least 3 different methods were found. One interesting solution was the addition of al the ones (1+11+21..+91 = 460) then all twos (2+12+22+…+92 = 470) etc.
Teacher Demonstration and Discussion
Practical: Observe students suggestions, pattern recognition, past algorithms, decomposition into sub problems
Observe the sum of pairs from out going in always sum to 200.
Determine the number of pairs.
Note that the steps to solve this problem are:
- Find the sum of the first and last numbers (1+200)
- Find the number of pairs (200/2)
- Multiply the results of 1 and 2.
Further Exersises and Discussion – Finding the Sum of a Range Of numbers
- Using a similar approach as shown above, write the set of steps to find the sum of numbers from 1 to 10
- Write the steps to find the sum of any range of numbers from which form a complete number of pairs. (e.g 5 to 10)
- Write the steps to find the sum of any range of numbers from which form an incomplete number of pairs. (e.g 5 to 11)
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