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A plan for solving problems
Textbook Part 3, pp. 6–7
GoalFollow a step-by-step plan (algorithm) to solve problems.
New words
algorithm (step-by-step plan) · algoritmplan · rejainformation / data · ma’lumot
Explanation
To solve any problem we make a plan: 1) pick out the data (what numbers are given?); 2) find the question (what do we need?); 3) write an expression; 4) calculate; 5) write the answer. This sequence of steps is called an algorithm.
Worked examples
Problem: A library received 25 storybooks and 14 encyclopedias. How many in all? 1) 25 and 14; 2) how many in total; 3) 25 + 14; 4) 39; 5) 39 books.
Algorithms are everywhere: making tea — boil water, put tea in the pot, pour the water, wait.
Class activity
“Robot commands”: one child is a robot and another gives step-by-step commands to reach the classroom door. A wrong command makes the robot stop.
Practice
1
Put the steps in order: calculate, find the question, write the answer, write an expression, pick out the data.
Data → question → expression → calculate → answer
2
A garden has 46 red and 32 white roses. How many in all? (use the plan)
78
3
A crate had 58 apples and 25 were sold. How many are left?
33
4
Follow the steps: 20 → +15 → −5 → +30
60