Chapter 3 · Place value and decimals

Ten Times as Much and One Tenth as Much

Learn how a digit is worth ten times as much one place to the left and one tenth as much one place to the right, in whole numbers and in decimals to thousandths.

15 min read

Look at the numbers 66 and 6060. Both use the digit 66, but the 66 does not stand for the same amount in each number.

A digit is one of the ten symbols from 00 to 99 that you use to write numbers. A place is the position of a digit in a number, such as the ones place or the tens place. The value of a digit is the amount it stands for in its place.

In 66, the digit 66 is in the ones place. It stands for 66 ones, so its value is 66. In 6060, the digit 66 is in the tens place. It stands for 66 tens, so its value is 6060.

So the same digit can stand for different amounts, and its place makes the difference. In this lesson, you will find out exactly how the value changes when a digit moves one place to the left or one place to the right.

Each row moves the digit 6 one place to the right
Place of the digit 6Value in wordsValue as a number
thousands place
66 thousands
6,0006{,}000
hundreds place
66 hundreds
600600
tens place
66 tens
6060
ones place
66 ones
66

Read down the last column of the table: 6,0006{,}000, 600600, 6060, 66. Then read it from the bottom up: 66, 6060, 600600, 6,0006{,}000. Do you see a pattern each way?

Going up one row, the digit 66 moves one place to the left, and its value becomes 1010 times as much. That means 1010 equal groups of the amount you had. For example, 1010 groups of 66 make 6060, so 6060 is 1010 times as much as 66.

Going down one row, the digit 66 moves one place to the right, and its value becomes one tenth as much. One tenth, which you write as 110\frac{1}{10}, is one of 1010 equal parts. To find 110\frac{1}{10} of an amount, split it into 1010 equal parts and keep one part. That is the same as dividing by 1010. For example, 6060 split into 1010 equal parts gives 66 in each part, so 66 is 110\frac{1}{10} of 6060.

The same is true for 66 hundreds and 66 tens. In words, 600600 is 1010 times as much as 6060, and 6060 is 110\frac{1}{10} of 600600. In numbers, it looks like this:

600=10×60and60=600÷10600 = 10 \times 60 \qquad \text{and} \qquad 60 = 600 \div 10

Key concept

Each place is worth 10 times the place to its right

A digit in one place stands for 1010 times what it stands for in the place to its right. It stands for 110\frac{1}{10} of what it stands for in the place to its left. This is true for any two places that are next to each other.

Worked example

The digit 7 in two places that are side by side

In 7,0007{,}000, the digit 77 is in the thousands place. In 700700, the digit 77 is in the hundreds place. How does the value of the 77 in 7,0007{,}000 compare with the value of the 77 in 700700?

  1. Write what the digit 7 stands for in each number, so that you can compare the two amounts. In 7,000 it stands for 7 thousands. In 700 it stands for 7 hundreds.

    7 thousands=7,0007 hundreds=7007 \text{ thousands} = 7{,}000 \qquad 7 \text{ hundreds} = 700
  2. The thousands place is one place to the left of the hundreds place. One place to the left means 10 times as much, so 7 thousands is 10 times as much as 7 hundreds. You can check it: 10 groups of 700 make 7,000.

    7,000=10×7007{,}000 = 10 \times 700
  3. Now compare in the other direction. The hundreds place is one place to the right of the thousands place. One place to the right means one tenth as much, and you find one tenth by dividing by 10.

    7,000÷10=7007{,}000 \div 10 = 700

Answer

The 77 in 7,0007{,}000 stands for 1010 times as much as the 77 in 700700. The 77 in 700700 stands for 110\frac{1}{10} of what the 77 in 7,0007{,}000 stands for.

The same pattern tells you how the places themselves are related. Think about what the digit 11 stands for in each place, starting at the ones place and moving left: 11, 1010, 100100, 1,0001{,}000, 10,00010{,}000. Each amount is 1010 times the one before it. So it always takes 1010 of one place to make 11 of the next place to the left:

  • 1010 ones make 11 ten.
  • 1010 tens make 11 hundred.
  • 1010 hundreds make 11 thousand.
  • 1010 thousands make 11 ten thousand.

Going the other way, 11 hundred is 110\frac{1}{10} of 11 thousand, because 1,000÷10=1001{,}000 \div 10 = 100.

You can link two of these facts to relate places that are farther apart. The next example shows how.

Worked example

From hundreds to ten thousand

How many hundreds make ten thousand?

  1. Start at the hundreds place and move one place to the left, to the thousands place. Each place is worth 10 times the place to its right, so 10 hundreds make 1 thousand.

    10×100=1,00010 \times 100 = 1{,}000
  2. Move one more place to the left, to the ten thousands place. For the same reason, 10 thousands make 1 ten thousand.

    10×1,000=10,00010 \times 1{,}000 = 10{,}000
  3. Link the two facts. Ten thousand is 10 thousands, and each of those thousands is 10 hundreds. That makes 10 groups of 10 hundreds.

    10×10=10010 \times 10 = 100
  4. Check the answer. If 100 hundreds make ten thousand, then 100 groups of 100 must equal 10,000. They do.

    100×100=10,000100 \times 100 = 10{,}000

Answer

It takes 100100 hundreds to make ten thousand.

The pattern does not stop at the ones place. Right after the ones place comes the decimal point, the dot that separates the ones place from the places for parts of 11. Each place after it is still worth 110\frac{1}{10} of the place to its left.

  • Tenths place. Split 11 into 1010 equal parts. Each part is one tenth, or 110\frac{1}{10}. You already write it as 0.10.1.
  • Hundredths place. Split each tenth into 1010 equal parts. Now 11 has 10×10=10010 \times 10 = 100 equal parts. Each part is one hundredth, or 1100\frac{1}{100}. You already write it as 0.010.01.
  • Thousandths place. Split each hundredth into 1010 equal parts. Now 11 has 100×10=1,000100 \times 10 = 1{,}000 equal parts. Each part is one thousandth, or 11,000\frac{1}{1{,}000}. You write it as 0.0010.001, with the 11 in the third place after the decimal point.

The table below follows the digit 66 into these places. One tenth of 11 is 11 tenth, so one tenth of 66 ones is 66 tenths.

The digit 6 keeps moving right, past the decimal point
Place of the digit 6Value in wordsValue as a numberCompared with one place to the left
ones place
66 ones
66
66 is 110\frac{1}{10} of 6060
tenths place
66 tenths
0.60.6
0.60.6 is 110\frac{1}{10} of 66
hundredths place
66 hundredths
0.060.06
0.060.06 is 110\frac{1}{10} of 0.60.6
thousandths place
66 thousandths
0.0060.006
0.0060.006 is 110\frac{1}{10} of 0.060.06

Now read the table from the bottom up. Going up one row still moves the digit 66 one place to the left, so each value is 1010 times as much as the value below it. This works because it takes 1010 thousandths to make 11 hundredth, 1010 hundredths to make 11 tenth, and 1010 tenths to make 11.

So 0.060.06 is 1010 times as much as 0.0060.006, 0.60.6 is 1010 times as much as 0.060.06, and 66 is 1010 times as much as 0.60.6. The digit 66 crossed the decimal point, and the pattern stayed the same.

Worked example

One place each way from the hundredths place

Answer both questions. 0.040.04 is 1010 times as much as what number? 0.040.04 is 110\frac{1}{10} of what number?

  1. Name the value in words. In 0.04 the digit 4 is in the hundredths place, so 0.04 is 4 hundredths.

    0.04=4 hundredths0.04 = 4 \text{ hundredths}
  2. In the first question, 0.04 is 10 times as much as the other number, so the other number is one tenth of 0.04. One tenth as much means one place to the right. The 4 moves from the hundredths place to the thousandths place and stands for 4 thousandths. Zeros fill the tenths and hundredths places.

    4 thousandths=0.0044 \text{ thousandths} = 0.004
  3. Check the first answer. It takes 10 thousandths to make 1 hundredth, so 10 groups of 4 thousandths make 4 hundredths.

    10×0.004=0.0410 \times 0.004 = 0.04
  4. In the second question, 0.04 is one tenth of the other number, so the other number is 10 times as much as 0.04. Ten times as much means one place to the left. The 4 moves from the hundredths place to the tenths place and stands for 4 tenths.

    4 tenths=0.44 \text{ tenths} = 0.4
  5. Check the second answer. It takes 10 hundredths to make 1 tenth, so 10 groups of 4 hundredths make 4 tenths. That means 4 hundredths is one tenth of 4 tenths.

    10×0.04=0.410 \times 0.04 = 0.4

Answer

The number 0.040.04 is 1010 times as much as 0.0040.004, and it is 110\frac{1}{10} of 0.40.4.

Here is the idea to keep. A digit in any place stands for 1010 times what it would stand for one place to the right. It stands for 110\frac{1}{10} of what it would stand for one place to the left. The same pattern links thousands and hundreds, ones and tenths, and hundredths and thousandths. The decimal point does not change it.

Next, you will compare what the same digit stands for in two places of one number, such as the digit 44 in 4.444.44.