Computer science fundamentals · Lesson 39 of 60 · Concept lesson · Optional

Binary and number systems

Computers store everything as bits, which are 0s and 1s.

Binary is base 2, where each place is worth twice the one to its right, while decimal is base 10 and hexadecimal is base 16.

Eight bits make a byte, which can hold 256 different values.

Picture it

binary    1   0   1   1
place     8   4   2   1
          8 + 0 + 2 + 1 = 11

The binary number 1011 read place by place. The places are worth 8, 4, 2 and 1, and adding the places that hold a 1 gives 11.

console.log((11).toString(2));
console.log(parseInt("1011", 2));

Output:

1011
11

toString(2) writes a number in binary, and parseInt with base 2 reads binary back.

print(format(11, "b"))
print(int("1011", 2))

Output:

1011
11

format(..., "b") writes a number in binary, and int with base 2 reads binary back.

Pick an answer for each question. You can retry as many times as you like.

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Computer science fundamentals · Lesson 39 of 60 · Concept lesson · Optional

Computers store everything as bits, which are 0s and 1s.

Binary is base 2, where each place is worth twice the one to its right, while decimal is base 10 and hexadecimal is base 16.

Eight bits make a byte, which can hold 256 different values.

binary    1   0   1   1
place     8   4   2   1
          8 + 0 + 2 + 1 = 11

The binary number 1011 read place by place. The places are worth 8, 4, 2 and 1, and adding the places that hold a 1 gives 11.

console.log((11).toString(2));
console.log(parseInt("1011", 2));

Output:

1011
11

toString(2) writes a number in binary, and parseInt with base 2 reads binary back.

print(format(11, "b"))
print(int("1011", 2))

Output:

1011
11

format(..., "b") writes a number in binary, and int with base 2 reads binary back.

Pick an answer for each question. You can retry as many times as you like.

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