All numbers are made up of digits: 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9. Digits are like letters in a word. A word is made up of letters. Numbers are made up of digits: 23 is a two-digit number, made from the digits 2 and 3; 627 is a three-digit number made from the digits 6, 2 and 7. The position of the digit in the number tells
us its value.
For instance, the 2 in the number 23 has a value of 2 tens, and the 3 has a value of 3 ones. Numbers in the hundreds are three-digit numbers: 435, for example. Th e 4 is the hundreds digit and tells us there are 4 hundreds (400). Th e tens digit is 3 and signifies 3 tens (30). Th e units digit is 5 and signifies 5 ones,
or simply 5. When we write a number, the position of each digit is important. The position of a digit gives that digit its place value. When we write prices, or numbers representing money, we use a decimal point to separate the dollars from the cents.
For example,
$2.50 represents 2 dollars and 50 hundredths of a dollar. The first digit after the decimal represents tenths of a dollar. (Ten 10¢ coins make a dollar.) Th e second digit after the decimal represents hundredths of a dollar. (One hundred cents make a dollar.) So $2.50, or two and a half dollars, is the same as 250¢. If we wanted to multiply $2.50 by 4, we could simply multiply the 250¢ by 4 to get 1,000¢. One thousand cents is the same as $10.00.
us its value.
For instance, the 2 in the number 23 has a value of 2 tens, and the 3 has a value of 3 ones. Numbers in the hundreds are three-digit numbers: 435, for example. Th e 4 is the hundreds digit and tells us there are 4 hundreds (400). Th e tens digit is 3 and signifies 3 tens (30). Th e units digit is 5 and signifies 5 ones,
or simply 5. When we write a number, the position of each digit is important. The position of a digit gives that digit its place value. When we write prices, or numbers representing money, we use a decimal point to separate the dollars from the cents.
For example,
$2.50 represents 2 dollars and 50 hundredths of a dollar. The first digit after the decimal represents tenths of a dollar. (Ten 10¢ coins make a dollar.) Th e second digit after the decimal represents hundredths of a dollar. (One hundred cents make a dollar.) So $2.50, or two and a half dollars, is the same as 250¢. If we wanted to multiply $2.50 by 4, we could simply multiply the 250¢ by 4 to get 1,000¢. One thousand cents is the same as $10.00.
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