Topic 1: Problem Solving

Question 1

What is an algorithm?

Answer 1

A set of instructions that perform a specific task
Or
A precise method for solving a problem

Question 2

What is the purpose of algorithm?

Answer 2

To visualise the logical steps of a task

Question 3

Key term:

Unambiguous

Answer 3

This means that the instructions cannot be misunderstood. Simply saying ‘turn’ would be ambiguous because you could turn left or right

Question 4

Key term:

Sequence

Answer 4

An ordered set of instructions

Question 5

Key term:

High-level programming language

Answer 5

A programming language that resembles natural human language

Question 6

Key term:

Flowchart

Answer 6

A graphical representation of an algorithm.
Each step in the algorithm is represented by a symbol.
Symbols are linked together with arrows showing the order in which steps are executed

Question 7

Written descriptions

Answer 7

The simplest way of expressing an algorithm.
E.g an algorithm for making a cup of instant coffee:
Fill kettle with water.
Turn on kettle.
Place coffee in cup.
Wait for water to boil.
Pour water into cup.
Add milk and sugar.
Stir.

Question 8

Key term:

Pseudo-code

Answer 8

A structured, code-like language that can be used to describe an algorithm

Question 9

Pseudo-code

Algorithm for adding two numbers

Answer 9

SEND ‘please enter the first number.’ TO DISPLAY

RECEIVE firstNumber FROM KEYBOARD

SEND ‘please enter the second number.’ TO DISPLAY

RECEIVE secondNumber FROM KEYBOARD

SET total TO firstNumber + secondNumber

SEND total TO DISPLAY

Question 10

Key term:

Variable

Answer 10

A ‘container’ used to store data. The data stored in a variable is referred to as a value. The value stored in a variable is not fixed. The same variable can store different values during the course of a program and each time a program is run

Question 11

Key term:

Identifier

Answer 11

A unique name given to a variable or a constant. Using descriptive names for variables makes code much easier to read

Question 12

Key term:

Arithmetic operator

Answer 12

An operator that performs a calculation on two numbers

Question 13

Arithmetic operator:

+

Answer 13

Addition: add the values together

Question 14

Arithmetic operator:

-

Answer 14

Subtraction: subtract the second value from the first

Question 15

Arithmetic operator:

*

Answer 15

Multiplication: multiply the values together

Question 16

Arithmetic operator:

/

Answer 16

Real division: divide the first value by the second value and return the result including decimal places

Question 17

Arithmetic operator:

DIV

Answer 17

Quotient: like division, but it only returns the whole number or integer

Question 18

Arithmetic operator:

MOD

Answer 18

Modulus/modulo: this will return the remainder of a division.
E.g 13/4=3 remainder 1. Therefore 13 MOD 4=1

Question 19

Arithmetic operator:

^

Answer 19

Exponentiation: this is for ‘to the power of’

Question 20

Key term:

Constant

Answer 20

A ‘container’ that holds a value that never changes. Like variables, constants have unique identifiers

Question 21

Key term:

Construct

Answer 21

A component from which something is built. Letters and numbers (I.e. A to Z and 0 to 9) are the constructs we use to build our language and convey meaning.