Book Image

Scratch 1.4: Beginner's Guide

Book Image

Scratch 1.4: Beginner's Guide

Overview of this book

If you have the imaginative power to design complex multimedia projects but can't adapt to programming languages, then Scratch 1.4: Beginner's Guide is the book for you. Imagine how good you'll feel when you drag-and-drop your way to interactive games, stories, graphic artwork, computer animations, and much more using Scratch even if you have never programmed before. This book provides teachers, parents, and new programmers with a guided tour of Scratch's features by creating projects that can be shared, remixed, and improved upon in your own lesson plans. Soon you will be creating games, stories, and animations by snapping blocks of "code" together. When you program you solve problems. In order to solve problems, you think, take action, and reflect upon your efforts. Scratch teaches you to program using a fun, accessible environment that's as easy as dragging and dropping blocks from one part of the screen to another. In this book you will program games, stories, and animations using hands-on examples that get you thinking and tinkering. For each project, you start with a series of steps to build something. Then you pause to put our actions into context so that you can relate our code to the actions on Scratch's stage. Throughout each chapter, you'll encounter challenges that encourage you to experiment and learn. One of the things you're really going to love is that, as you begin working through the examples in the book, you won't be able to stop your imagination and the ideas will stream as fast as you can think of them. Write them down. You'll quickly realize there are a lot of young minds in your home, classroom, or community group that could benefit from Scratch's friendly face. Teach them, please.
Table of Contents (17 chapters)
Scratch 1.4 Beginner's Guide
Credits
About the Author
About the Reviewer
Preface
Scratch Resources
Index

Chapter 8. Math and Finance

If I offered you $15,000 or one dollar that doubled every day for 30 days, which one would you choose? By the time we finish the chapter, you'll know if you've chosen wisely.

We'll use the Indian folktale by Demi, "One Grain of Rice," to inspire our project and to demonstrate the power of doubling. In the folktale, a village girl asks a greedy king to double a single grain of rice each day for thirty days as a way to accumulate enough rice to feed the hungry villagers.

In this chapter, we will illustrate the math behind the folktale and compare it to conventional interest-based accrual methods. Specifically, we will:

  • Calculate the total amount of money if we double a dollar each day

  • Collect user input via slider input controls

  • Graph the results of a calculation using the pen and stamp tools

  • Build interactive math problems using variables

  • Calculate simple interest on an amount of money

I'm using dollars as the basis for my project, but the math works whether we use euros...