Writing Numbers as Words/Numerals

Our number system is a base-10 system. Every place value in our number system is greater than the place value to the right by a factor of 10. So, if you have the number 22, the 2 in the ones column is worth 2 ones. The 2 in the tens column is worth 20 (2 x 10 = 20).

Learning to read numerals as words (and convert number words into numerals) is based mostly upon understanding place value and the digits 0-9. Before learning to name two-digit numbers, students should know the numbers 0-9 perfectly.  

Most of the number naming conventions in the English language are standardized (a number with 3 in the hundreds place is "three hundred" and a number with 6 in the thousands place is "six thousand"), but the tens are stylized (and those stylizations continue through the number system: 60 becomes sixty-thousand, sixty-million, etc.), so students should also learn the tens numbers by heart:

A student who can count by tens probably knows these naming conventions.

After that, naming two-digit numerals is just a matter of combining the tens place word with the ones place word.

Example:

33 = thirty three

79 = seventy nine

81 = eighty one

Remind students that they never say the zero in the ones place.  If there is a zero in any place value, they do not name it.  A zero in the ones place means you just name the tens place number.

Three digit numbers follow the same pattern, you name the hundreds place digit, followed by the word "hundred," then name the tens place number, then the ones place word:

333 = three hundred thirty three

790 = seven hundred ninety

801 = eight hundred one

Notice that when there is a zero in a place value, students don't name that place value at all.

After the hundreds place, our numeral naming conventions move in three-digit chunks. You use the conventions above to name the three digit set, then you add the name of the entire set, then you move on to the next set.  Sets are named after the place value of the first (farthest right) digit of the set. See the set names below:

$\overset{\text{billion}}{\large{123,}} \underset{\text{million}}{\large{456,}} \overset{\text{thousand}}{\large{789,}}\large{987}$

To name the number above, students name each three digit chunk that lies between commas and then at the end of that chunk, gives the chunk name.  They end with the final chunk which has no chunk name. 

$\overset{\text{billion}}{\large{123,}} \underset{\text{million}}{\large{456,}} \overset{\text{thousand}}{\large{789,}}\large{987}=$

$\text{one hundred twenty three billion, four hundred fifty six million, seven hundred eighty nine thousand, nine hundred eighty seven}$

The rules for each three-digit chunk is the same for naming a three digit number, students just have to add the chuck name (see lesson Place Value for more on number naming past the billions).

Note: Do not use the word "and" when naming whole numbers.  345 is "three hundred forty five," NOT "three hundred and forty-five."  In math, "and" represents a decimal (3.45 = three and 45 hundredths).  So, don't allow young kids to get into the habit of using "and" with whole numbers.