Egypt Primary 4 Mathematics, Week 1: One number, many ways to write it

Digits, numerals and really big numbers

Week 1 · Digits, numerals and really big numbers · 3 lessons

One number, many ways to write it

Discover Mathematics P4: Term 1, Unit 1, Lessons 1–6

GoalWrite a number in standard, word and expanded form, and make the greatest and smallest numbers from digit cards.

New words

standard form · the number written with digits and commasword form · the number written in wordsexpanded form · the number written as a sum of the values of its digits

Explanation

One number can be written in three ways. Standard form uses digits: 6,235,678. Word form uses words: six million, two hundred thirty-five thousand, six hundred seventy-eight. Expanded form adds the value of each digit: 6,000,000 + 200,000 + 30,000 + 5,000 + 600 + 70 + 8. We leave out digits that are 0, because they add nothing. To make the greatest number from digit cards, put the biggest digit in the highest place and go down. To make the smallest number, put the smallest digit first, but not 0 in the first place, because 0 at the front adds nothing. From the cards 3, 0, 7, 9, 5 the greatest number is 97,530 and the smallest is 30,579.

Form	Number 6,235,678
Standard	6,235,678
Expanded	6,000,000 + 200,000 + 30,000 + 5,000 + 600 + 70 + 8

Worked examples

Place	millions	ten thousands	hundreds
Value	4,000,000	70,000	300

Write 4,070,300 in expanded form. The digits are 4 millions, 7 ten thousands and 3 hundreds, and the other places hold 0. So 4,070,300 = 4,000,000 + 70,000 + 300.

Millions period	Thousands period	Ones period
53	000	406

Write the expanded form 50,000,000 + 3,000,000 + 400 + 6 in standard form. Put each value in its place and fill the empty places with zeros: 53,000,406.

Cards	Greatest	Smallest
8 2 6 0 4	86,420	20,468

Youssef has the digit cards 8, 2, 6, 0 and 4. Greatest number: put the digits from biggest to smallest, 86,420. Smallest number: 0 cannot go first, so start with 2 and then 0, 4, 6, 8, which gives 20,468. The difference is 86,420 − 20,468 = 65,952.

Class activity

Number battle. Each player writes any seven-digit numeral on paper, for example 5,208,360. Take turns to read your number aloud in words, then write it in expanded form. The player who does it without a mistake gets a point. Swap papers and check each other.

Practice

Write 8,305,000 in expanded form.

Write 700,000 + 20,000 + 9 in standard form.

Make the greatest number from the cards 1, 5, 9, 3, 7.

Make the smallest number from the cards 5, 0, 9, 2 and 7 (use every card once).

Write 40,003,010 in words.