22
Showing an algorithm as a picture
Textbook: pp. 56–58
GoalKnow how to show an algorithm as a flowchart and the jobs of the oval, the rectangle and the arrow.
New words
flowchart · blok-sxemaoval · ovalrectangle · to‘g‘ri to‘rtburchakarrow · strelka
Explanation
An algorithm can also be written as a diagram, called a flowchart. Each action goes into its own shape. An oval shows the start and the end. A rectangle shows one action. An arrow shows the order of actions. A flowchart always begins with a “Start” oval and finishes with an “End” oval.
Worked examples
Going to school: (Start) → [reach the crossroads] → [cross the road] → [enter school] → (End).
One action means one rectangle. Three actions mean three rectangles.
Class activity
“Living flowchart”: one child holds a “Start” oval, three hold action cards (“turn on the tap”, “soap your hands”, “rinse”), and one holds an “End” oval. They stand in the right order along paper arrows.
Practice
1
Which shape shows the start and the end of an algorithm?
an oval
2
Which shape holds each action?
a rectangle
3
“Brushing teeth”: [put on paste] → [take the brush] → [clean the teeth] → [rinse]. Which two actions must swap places?
“put on paste” and “take the brush”