Big Numbers!
Changing Values
The value of each digit in any number depends on its place in this number.
For Example:
The least distance from the Earth to the moon is 384,402 km.
Notice the value of each digit in the number 384,402.
Note that:
To make large numbers easier to read, we group digits into sets of three called periods. Each period always includes a place for ones, tens, and hundreds.
Example 1
Write the place value and the value of the colored digit.
a. 79,285
b. 980,758
c. 29,510
d. 220,089
Solution 💡
Million
- You know that the greatest 6-digit number is 999,999. The number which comes just after 999,999 is 1,000,000, which is the smallest 7-digit number.
- To show 1,000,000 in the place-value chart, a period for Millions has to be added to the left of the Thousands period.
More about millions
Egypt population in 2020 was 102,334,404. Look at this number on the place-value chart.
This number read as:
One hundred two million, three hundred thirty-four thousand, four hundred four.
or in a short way: 102 million, 334 thousand, 404
Example 2
What is the place value and the value of each underlined digit?
583,460,905
Solution 💡
Milliard (Billion)
China has the world's largest population. In 1980, the population of China reached about 1,000,000,000. It is read as one milliard (or one billion).
To show 1,000,000,000 in the place-value chart, a column for Milliards has to be added to the left of the Millions period.
More about milliards
The world's population in 2020 was about 7,794,798,739. Look at this number on the place-value chart.
This number read as:
Seven milliard, seven hundred ninety-four million, seven hundred ninety-eight thousand, seven hundred thirty-nine.
or in a short way: 7 milliard, 794 million, 798 thousand, 739
How to read a large number?
Divide the number (from right to left) into "periods" each period contains 3 digits.
Use the place-value chart to help you read the large number.
Start from the left and read the number in each period followed by the period name as follows.
Six milliard, two hundred eight million, one hundred ninety-six thousand, three hundred eighteen.
In a short way: 6 milliard, 208 million, 196 thousand, 318
Example 4
Choose the correct answer.
1. 4 milliard, 103 million, 905 thousand, 484 = __________
A. 43,509,458
B. 403,590,548
C. 4,103,905,484
D. 4,950,854
2. Forty-three million, five hundred nine thousand, four hundred fifty-eight = __________
A. 43,509,458
B. 403,590,548
C. 4,103,905,484
D. 4,950,854
3. 403 million, 590 thousand, 548 = __________
A. 43,509,458
B. 403,590,548
C. 4,103,905,484
D. 4,950,854
4. The value of the digit 3 in the Hundreds place is __________
A. 3
B. 30
C. 300
D. 3,000
Solution 💡
- The value of a digit changes as it moves to the left within a number.
- Our place-value system is based on tens. Each place value in this system is 10 times the one to the right of it.
- A digit in one place equals 10 times the digit in the place to its right.
- For Example: The Hundreds place is 10 times the Tens place, so the value of 2 changes from 20 to 200.
- Observe the pattern in the number of zeroes.
Example 5
Fill in the blanks below.
a. The value of the digit 3 in the number 7,431,210 equals __________ times the value of the digit 3 in the number 4,563,809
b. The value of 7 in the Thousands place = __________ times the value of 7 in the Tens place.
c. __________ is 10 times one hundred thousand.
d. 30 tens equals __________
e. 7,000 thousands = __________ millions.