الأسبوع 1 · الأرقام والأعداد الكبيرة جدًا · 3 دروس
2
Building numbers into the billions
Discover Mathematics P4: Term 1, Unit 1, Lessons 1–6
GoalRead and write numbers up to the billions using the place value chart and its periods.
New words
period · a group of three places: ones, thousands, millions, billionsmillion · one thousand thousands, written 1,000,000billion · one thousand millions, written 1,000,000,000
Explanation
Big numbers are easier to read when we split them into periods of three digits, counting from the right. The periods are ones, thousands, millions and billions, and a comma separates them. Inside each period there are three places: hundreds, tens and ones. To read 2,450,890,007, read each period as a three-digit number and then say the name of the period: two billion, four hundred fifty million, eight hundred ninety thousand, seven. We do not say the name of the ones period. Ten places go from 7 ones up to 2 billions. A zero is written in a place with nothing in it, so 2,450,890,007 has a 0 in the thousands, hundreds and tens places.
Billions
Millions
Thousands
Ones
2
450
890
007
Worked examples
Millions
Thousands
Ones
6
235
678
Read 6,235,678. The periods are 6 | 235 | 678. We say six million, two hundred thirty-five thousand, six hundred seventy-eight.
Billions
Millions
Thousands
Ones
9
231
043
204
The number 9,231,043,204 has four periods: 9 | 231 | 043 | 204. The 9 is in the billions place, so it is worth 9,000,000,000. The 3 is in the ten millions place, so it is worth 30,000,000. The digit 4 appears twice. The first 4 is in the ten thousands place and is worth 40,000. The last 4 is in the ones place and is worth 4.
Name
thousand
million
billion
Number
1,000
1,000,000
1,000,000,000
Zeros
3
6
9
One thousand millions make one billion. 1,000 × 1,000,000 = 1,000,000,000. A billion has nine zeros. So 1,000,000,000 is ten times as big as 100,000,000.
Class activity
Count the zeros. Write the numbers one thousand, ten thousand, one hundred thousand, one million and ten million on strips of paper, each with its comma. Put them in order from the smallest to the biggest and count the zeros in each one. Notice that every number has one more zero than the number before.
Practice
1
Write in digits: five million, three hundred two thousand, forty.
5,302,040.
2
In 7,408,215 what is the value of the digit 4?
It is in the hundred thousands place: 400,000.
3
How many periods does 83,500,016,900 have? Read the number.
Four periods. Eighty-three billion, five hundred million, sixteen thousand, nine hundred.
4
Which place does the digit 6 hold in 6,000,000,000, and how many zeros follow it?
The billions place, followed by nine zeros.
5
Ahmed wrote ten million as 1,000,000. What did he write? Fix it.
