☰ Year plan · Mathematics

Digits, numerals and really big numbers

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

Digit, numeral or number?

Discover Mathematics P4: Term 1, Unit 1, Lessons 1–6
GoalTell a digit, a numeral and a number apart, and read the value of a digit from its place.
New words
digit · one of the ten symbols 0, 1, 2, 3, 4, 5, 6, 7, 8, 9numeral · the way a number is written, using one or more digitsnumber · how many there are; an amountplace value · what a digit is worth because of where it stands
Explanation

We build every number from only ten digits: 0 to 9. A digit is like a letter, and a numeral is like a word made from letters. The numeral 3,075 is made of the digits 3, 0, 7 and 5. The number is the amount that the numeral tells us. Where a digit stands matters. In 3,075 the digit 7 stands in the tens place, so it is worth 70. In 3,750 the same digit 7 stands in the hundreds place and is worth 700. The digit 0 is a place holder: it keeps the other digits in their right places, so 3,075 is not the same as 375. Always ask two questions about a digit: which digit is it, and in which place does it stand?

Digit3075
Placethousandshundredstensones
Value3,0000705
Worked examples
Digit4908
Value4,00090008
Mariam writes her bus ticket number, 4,908. The digits are 4, 9, 0 and 8, four digits in all. The numeral 4,908 stands for the number four thousand nine hundred eight. The digit 9 is in the hundreds place, so it is worth 900.
Numeral550500
Place of 5onestenshundreds
Value550500
The digit 5 appears in three numerals: 5, 50 and 500. In 5 it is worth 5 ones. In 50 it is worth 5 tens, which is 50. In 500 it is worth 5 hundreds, which is 500. The digit is the same but its value changes with its place.
Numeral2,00626
Value of the 22,00020
Omar says 2,006 and 26 are the same because both have a 2 and a 6. He is wrong. In 2,006 the 2 is worth 2,000 and the two zeros hold the tens and hundreds places. In 26 the 2 is worth only 20. The numerals 2,006 and 26 name two different numbers.
Class activity

Digit cards. Write the digits 0 to 9 on ten small papers. A grown-up and the child each pick 4 papers and make a four-digit numeral. They read the number aloud, then each says the value of the biggest digit. The one whose digit has the greater value wins the round.

Practice
1
How many digits are in the numeral 7,420? Name them.
2
What is the value of the digit 6 in 8,630?
3
Write a numeral with the digit 4 worth 40 and the digit 9 worth 9,000.
4
Is the digit 0 worth anything in 5,080? Why do we write it?
5
Farida says the numeral 303 has two different digits. Is she right?