Unit 1: Number Concept

In this unit you will master numbers all the way up to 8 digits. You will read and write them, compare them, round them, and learn special number systems used in everyday life — Arabic Indic numerals and Roman numerals.

You already learned numbers up to 6 digits in grade 4. Numbers help us think logically, spot patterns and see how numbers relate to each other.

A place-value chart splits a number into Hundred thousands / Ten thousands / Thousands / Hundreds / Tens / Ones. For example, 268,946 = 2 HTh, 6 TTh, 8 Th, 9 H, 4 T, 6 O.

Counters on a chart show a number. Count how many of each place value, then put the digits in order from the biggest place to the smallest. 5 hundred-thousands + 6 ten-thousands + 3 thousands + 0 hundreds + 4 tens + 2 ones = 563,142.

Count in hundred thousands: 100,000 → 200,000 → … → 1,000,000. 1,000,000 is one million. 7-digit numbers start at 1,000,000 and go up to 9,999,999. More than 1,830,000 people performed Hajj in 2024 — that's a 7-digit number!

Every digit has a place and a value:

Add them all and you get 3,684,215.

Standard form is the digits written together: 1,242,960. Expanded form breaks it apart: 1,000,000 + 200,000 + 40,000 + 2,000 + 900 + 60. Practise switching between standard form, expanded form and number names.

Look at 7,956,238. Each digit lives in a place: 7 millions, 9 hundred thousands, 5 ten thousands, 6 thousands, 2 hundreds, 3 tens, 8 ones. To find a digit's value, multiply it by the value of its place.

The selling price of a house is MVR 3 million (3,000,000). If you pay with 1,000-rufiyaa notes, how many notes do you need? Hint: how many thousands are in 3 million?

Read the words carefully and translate to digits, place by place. 'Seven hundred and fifteen thousand, two hundred and thirty-nine' = 715,239. Watch out for zeros — 'Nine hundred and fifty thousand and two' = 950,002 (no hundreds, no tens!).

Use the digit cards 7, 3, 3, 5, 5, 6, 0 to build my 7-digit number where:

Try it on paper, then think about how many answers are possible.

Ten million is 10 × one million = 10,000,000. 8-digit numbers start at 10,000,000 and end at 99,999,999. We use these for populations of cities, distances, and country-wide totals.

23,674,815 = 20,000,000 + 3,000,000 + 600,000 + 70,000 + 4,000 + 800 + 10 + 5. In words: twenty-three million, six hundred and seventy-four thousand, eight hundred and fifteen.

Count backwards from 46,890,740 in ten millions: subtract 10,000,000 each step → 36,890,740 → 26,890,740 → 16,890,740 → 6,890,740. Only the ten-millions digit changes.

Number tracks reveal a rule. 2,120,000 → 2,220,000 → 2,320,000 → … the rule is +100,000 each step. Find the rule first, then fill in the blanks.

Practise moving freely between standard form, expanded form, and English/Dhivehi number names — for 8-digit numbers too. 90,000,000 + 8,000,000 + 70,000 + 6,000 + 500 + 30 = 98,076,530.

Populations of countries on 16 July 2023:

Compare the digits from the highest place down to find the biggest.

Big numbers are easier to say in 'millions': 1,500,000 can be written as 1½ million or 1.5 million. 5,250,000 = 5¼ million = 5.25 million. Newspapers say '1.83 million' instead of '1,830,000'.

Take 4,250,000. Put a decimal between millions and hundred thousands, then drop the trailing zeros: 4.25 million. Or just divide by 1,000,000: 4,250,000 ÷ 1,000,000 = 4.25. Either way, same answer.

Three students wrote 'five and three-quarters of a million' in numerals:

Only one is right. Three-quarters means ¾, which equals 0.75.

A news headline says 'Approximately 7 million people watched the final match'. The exact number might be 6,834,520 or 7,212,889 — we rounded it. Rounding makes a number simpler to use, but a bit less accurate.

4 steps:

Example: 1,834,525 to the nearest million → look at the hundred-thousands digit (8). 8 ≥ 5 → round up → 2,000,000.

Practise rounding the same number to different places. 5,750,999 rounds to:

The rules don't change — only the place you're looking at.

A number rounds to 4,000,000 (nearest million) when it lies between 3,500,000 and 4,499,999. Check the hundred-thousands digit: if the number is in the 4-millions, that digit must be 0–4. If it's in the 3-millions, that digit must be 5–9.

Arabic Indic numerals are the original digits used across the Arab world. They look different but mean the same:

٠=0, ١=1, ٢=2, ٣=3, ٤=4, ٥=5, ٦=6, ٧=7, ٨=8, ٩=9.

They combine just like our digits: ٢٣ = 23, ٥٢ = 52.

Arabic Indic numerals are used in the Hijri (Islamic) calendar. Rabi-ul-Awwal 1 marks the day the Maldives first embraced Islam. Use a calendar to match Gregorian dates with their Hijri equivalents.

Roman numerals use letters as numbers:

Combine them: VI = 6, IX = 9 (one less than ten), XV = 15, XX = 20, XXIX = 29. Putting a smaller letter before a larger one subtracts; putting it after adds.

Roman numerals are read in chunks. XVII = X (10) + V (5) + I + I (1+1) = 17. XIV = X (10) + IV (5−1=4) = 14. Always check whether each letter is added or subtracted.

Many old clocks use Roman numerals for the hours. III = 3, VI = 6, IX = 9, XII = 12. When you look at a clock with Roman numerals, you read the hour just like normal digits.

I am a 7-digit number.

Put them together: 9,678,344.

You can do simple math in other numeral systems too — convert to digits, calculate, convert back.

On a cheque the amount is written in figures AND words — they must match exactly. MVR 1,280,975 in words is 'One million, two hundred and eighty thousand, nine hundred and seventy-five'. Be careful — saying 'two hundred thousands and eighty thousands' is wrong!

Time to check yourself! Use what you know about place value to find the value of a single digit in a big number.

Big numbers often appear as a fraction or decimal of a million. Match the pairs that mean the same thing:

Look at Dhaana's apartment door. The number plate reads XVI — a Roman numeral. XVI = X + V + I = 10 + 5 + 1 = 16. You'll see Roman numerals on doors, clocks and book chapters, and Arabic Indic numerals on the Quran and Hijri calendars.

Look back over Unit 1. Ask yourself:

Great learners notice both their wins and their mistakes!