CSP Unit 1 Review

True or False: "bit" is short for "binary digit"

• True

• False

True or False: 8 bits makes 1 byte. The maximum decimal (base 10) value that can be represented by one byte is 256.

• True

• False

Answer explanation

It's true that 8 bits = 1 byte. It is also true that you can represent 256 total values with 1 byte.

HOWEVER - the maximum 8 bit number is 255 (decimal/base 10) since you have to include zero (0) in the values you can represent.

256 (decimal/base 10) is the first 9 bit number.

True or False: A computer represents data as bytes, which can either represent a 0 or a 1.

• True

• False

Answer explanation

A computer represents data as BITS, which can be either a zero or a one.

A byte is 8 bits.

Which of these is the best definition of abstraction?

• Abstraction allows us to represent complex information or perform complex tasks by showing underlying complexity.

• Abstraction allows us to represent complex information or perform complex tasks by hiding underlying complexity.

• Programming in machine language (binary) instead of a programming language like Python.

• None of these are a good definition.

Which of these best describes storing analog information digitally?

• Downloading a song from the internet and texting it to a friend.

• Using sampling to store an image in an analog format.

• Recording a video of a parade with your phone.

• None of these.

Answer explanation

The downloaded song from the internet is already digital.

Sampling does not result in an analog artifact.

A computer uses 3 bits to represent decimal (base 10) numbers. Which of these decimal values would result in an overflow error?

• 3

• 4

• 7

• 8

Answer explanation

The maximum three bit number is 111 (binary) = 7 (decimal).

8 would cause an overflow because you need 4 bits to represent 8 (1000 (binary) = 8 (decimal))

Which of these is the best explanation for round-off errors?

• A fixed number of bits can only represent a limited amount of precision.

• A fixed number of bits can represent any number.

• A fixed number of bits can represent infinitely repeating decimal fractions, but not irrational numbers like Pi.

• Round off errors won't ever happen as long as you use 64 bits.

Convert the binary (base-2) number 10101 to decimal (base-10)

• 8

• 12

• 21

• 42

Answer explanation

10101 =

1*(2^4) + 0*(2^3) + 1*(2^2) + 0*(2^1) + 1*(2^0) =

1*16 + 0*8 + 1*4 + 0*2 + 1*1 =

16 + 0 + 4 + 0 + 1 =

21

True or False: Even binary numbers will always end in 1, while odd binary numbers will always end in 0.

• True

• False

Convert the decimal (base 10) number 42 to binary (base-2)

• 0101

• 101010

• 1100101

• 10111

Answer explanation

Using your flippy do, the first place value that fits in to 42 going from left to right is 32, so that place becomes a 1.

42 - 32 is 10, the next place value, 16, is too big, so that becomes a 0.

8 fits, so that place value becomes a 1. Now you have 10-8 = 2 left. 4 is too big, so that place becomes a 0. 2 fits in to 2, so that place value becomes a 1. You have nothing left, so the ones place is a zero.

Stitch it all together = 101010