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The purpose of this module is to teach you about operators and operands in general and arithmetic operators in particular. You will also learn about expressions and statements, and you will learn how to write a Scratch program that illustrates the use of arithmetic operators in Scratch.

Table of contents

Preface

Scratch 2.0 (released May 9, 2013) is the second major version of Scratch to be released during the life of theproduct. Among other things, it features a redesigned editor and website, and allows you to edit projects directly from your web browser.

This module is one in a collection of modules designed to help beginners of all ages (8 and up) learn how to create the code for computer programs using Scratch 2.0 . Information is provided not only for the beginners themselves but also for their parents and teachers where appropriate.

The purpose of this module is to teach you about operators and operands in general and arithmetic operators in particular. You will also learn about expressions and statements, and you will learn how to write a Scratch program that illustrates the use of arithmetic operators in Scratch.

I will also provide the specifications for a student-programming project for you to complete in order to demonstrate your understanding of what you learnedfrom the first program.

Viewing tip

I recommend that you open another copy of this module in a separate browser window and use the following links to easily find and view the images while you are reading about them.

Images

  • Image 1 . Reduced screen shot of Arithmetic01 programming interface.
  • Image 2 . Expanded view of the rightmost panel.
  • Image 3 . Preparing to use the arithmetic operators.
  • Image 4 . Result of dropping addition and subtraction operators into variable blocks.
  • Image 5 . Stage area of the finished program.
  • Image 6 . Making the button say ouch.
  • Image 7 . Output from student project program named Arithmetic02.

General background information

Operators

Operators are the action elements of a computer program. They perform actions such as adding two variables, dividing one variable by another variable,comparing one variable to another variable, etc.

Questions & Answers

why is economics important
Derrick Reply
What will you do as a consumer if you are not at equilibrium?
chukwu Reply
am new I will like to know about the graph relationship
Gloria Reply
comment on WTO principle on trading system. trade without discrimination
Omben Reply
optimize z=f(x,y)=6x²-9x-3xy-7y+5y²
Alex Reply
What is an indifference curve?
layla Reply
different levels of utilities of a person in a given set of bundles of goods
RAM
identify and quantify five social costs and social benefits of building a school
Mokgobo Reply
identify and quantity five social costs and social benefits of building a hospital
Mokgobo
short run vs long run
Jean
state the law of diminishing return?
Ibrahim
The Law of Diminishing (Marginal) Returns simply states that at some point in time a business/operation/etc.'s increased productivity will begin to decline.
The
For example, if a small pizza shop currently has 3 workers in the kitchen at any given time,and hiring 1 more worker will increase productivity, at some number of workers hired will the business see a decrease in productivity because the capital resources that the pizza shop has is not infinite.
The
Five social benefits of building a hospital, in my opinion and depending on where it's built, would be 1) Increased care for neighboring residents, 2) Potential jobs for individuals, 3) May decrease the travel time residents need to endure in order to reach the nearest hospital
The
4) May create work-study programs for individuals who aspire to be future Doctors, Nurses, Physicians, etc. 5) Assuming there are local pharmaceutical businesses nearby, the hospital may decide to purchase supplies local, increasing the business' sales. Thus, generating more income.
The
5 costs of building a hospital would be 1) Increased noise and waste pollution from service vehicles and hospital visitors, 2) May require large amounts of space, possibly jeopardizing nearby animal habitats, 3) May see an increase in traffic and possibly car accidents from frantic individuals
The
racing to see their injured friends, family members, etc. 4) Constructing a hospital and hiring staff is very expensive 5) To use funds, private or public, to finance the construction of a hospital cannot be used to fund any other projects. (The concept of opportunity costs.)
The
what is meant by inteference with the price mechanism operation?
Mugen
We use a Supply and Demand graph to illustrate at what price level will the market for a certain good or service be at equilibrium. If the price for a good or service is set too high, consumers will be less inclined to buy that product Thus, creating a surplus.
The
This surplus will eventually drive the price back down to it's equilibrium point. Similarly, if a price for a good or service is set too low, individuals would be more inclined to buy more of a certain product, creating a shortage. This shortage will cause sellers to drive the price back up to the
The
equilibrium point.
The
is it true that the opportunity cost of unemployed labour is zero?
Wisdom Reply
no
Oigebe
give two forms of collusion
nondumiso Reply
1.Explicit Collusion: Also termed overt collusion, this occurs when two or more firms in the same industry formally agree to control the market .
Gafar
2.Implicit Collusion: Also termed tacit collusion, this occurs when two or more firms in the same industry informally agree to control the market, often through nothing more than interdependent actions. A prime example of implicit collusion is price leadership .
Gafar
explicit collusion: this occurs when two or more firms in the same industry legally agree to control the market
Panashe
implicit collusion this occurs when two or more firms in the same industry illegally agree to control the market
Panashe
what is responsible for investigating cases of collusion
nondumiso
what mean economic as a science
Godwin
reasons why a country maybe involved in international trade
Nde Reply
state five similarities and differences between money market and capital market
Victoria Reply
Give a Zimbabwean example of firms operating in an oligopoly market and illustrate using diagrams how a manager in such a market maximize profit
Pam Reply
what is an industry
EWAH Reply
An industry is the production of goods and related services within an economy
Prabhu
an industry is place where goods and services are produced for human consumption....
Usman
scarcity is the major course of economics problems. discuss
Abdulhameed Reply
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Abayneh
what is economics
Michael Reply
economics is a social sciences that deals with the production distribution and consumption of goods and services produced.its study of behaviour between economic agents
rkesh
what is the formula for elasticity of demand
Ridwan
change in demand/change in variable variable may be price, income,
rkesh
in a comparison of the stages of meiosis to the stage of mitosis, which stages are unique to meiosis and which stages have the same event in botg meiosis and mitosis
Leah Reply
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Source:  OpenStax, Teaching beginners to code. OpenStax CNX. May 27, 2013 Download for free at http://cnx.org/content/col11498/1.20
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