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Computer Systems. Nat 4/5 Computing Science Lesson 1: Binary. Section Key Terms. KEY WORDS. Section Key Words. Lesson Aims. By the end of this lesson: You will be able to: Describe what an integer is Represent positive integers in binary using up to 8 Bits
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Computer Systems Nat 4/5 Computing Science Lesson 1: Binary
Section Key Terms KEY WORDS Section Key Words
Lesson Aims • By the end of this lesson: • You will be able to: • Describe what an integeris • Represent positive integers in binaryusing up to 8Bits • State threeadvantages of the binary number system
Nat 4/5 The Decimal & Binary Systems • We use the decimal(denary) or base 10 system • This means we have 10digits : 0-9 • Computers use the binary or base 2 system • There are only twodigits: 0 and 1 • Each figure is known as a bit • Binary digit Because of our ten fingers? Off and On
Nat 4/5 Decimal Numbers • Lets look at how a decimal number is made up: 173 • Technically this is:
Nat 4/5 Binary Numbers • Lets look at how the same number is stored in binary: 1010 1101 • This number is constructed as shown above. • These values come from:
Nat 4/5 How to convert into Binary • Let’s look at the same example: • 173/2 = 86 r 1 • 86/2 = 43 r 0 • 43/2 = 21 r 1 • 21/2 = 10 r 1 • 10/2 = 5 r 0 • 5/2 = 2 r 1 • 2/2 = 1 r 0 • 1/2 = 0 r 1 • Binary Number = 1010 1101 Our binary number is: 1010 1101 Read the binary number from bottom up . This is our binary number
Nat 4/5 How to convert into Binary • Using the number 173 earlier. The aim is to subtract the values from the number until we are left with 0. • Can we subtract 128 from 173? • Yes – So we add a 1 to our number • Can we subtract 64 from 45? • No so we add a 0 • Can we subtract 32 from 45? • Yes so we add a 1 • Can we subtract 16 from 13? • No so we add a 0 • Can we subtract 8 from 13? • Yes so we add a 1 • Can we subtract 4 from 5? • Yes so we add a 1 • Can we subtract 2 from 1? • No so we add a 0 • Can we subtract 1 from 1? • Yes so we add a 1 Read the binary number from top down Our binary number is: 1010 1101
Nat 4/5 How to convert from Binary • Create your table with the values in the top • Insert your binary value into the table • Add the place values that have a binary 1 in them: 64+32+4+2 = 102
Nat 4/5 Advantages of the Binary system
Nat 4/5 Summary • Binary only has two values– 0 & 1 • A single 0 or 1 is known as a bit • Binary Digit • The place values in binary start on the right at 1 and double every time going to the left. Advantages of Binary: • There are less rules of arithmetic. • 0’s and 1’s are easier to represent. • Any drop in voltage doesn’t effect data.