Hong Kong Money

Foundation

Hong Kong dollars (HKD): coins of 10c, 20c, 50c, $1, $2, $5, $10.

For:Primary 1 Mathematics · Unit:Money · Lesson 20 of 21 in the learning path

After this lesson, you can:
  • HK coins: 10c, 20c, 50c, $1, $2, $5, $10.
  • $1 = 100 cents (ten 10c).
  • Count money by adding each coin.
數學Mathematics
Before this lesson you should know: Counting 1 to 100

1Summary 重點摘要

Hong Kong dollars (HKD): coins of 10c, 20c, 50c, $1, $2, $5, $10.

2Vocabulary cards Vocabulary

D
Dollar元(圓)

HKD unit, symbol $.

C
Coin硬幣

Money made of metal.

N
Note紙幣

Money made of paper.

T
Ten cents一毫

One tenth of a dollar.

F
Fifty cents五毫

Half a dollar; two of them make $1.

P
Price價錢

How much a thing costs.

P
Pay付款

Give money to the seller.

C
Change找續

Money given back when you pay too much.

3Step by step Steps

  1. Step 1: Know the coinsHong Kong has seven kinds of coins: 10c, 20c, 50c, $1, $2, $5 and $10, and they differ in size, thickness and colour. Example: the 10c coin is the smallest, the $10 coin is bigger and thicker, and the 20c and $2 coins have special wavy edges. Before buying anything, learn the value of every coin so the right money is paid. A common mistake is judging by size without reading the number; every coin carries its value on its face, and the printed number is what counts.
  2. Step 2: Know the exchangeSmall coins and dollar coins can be exchanged: one dollar equals ten 10-cent coins, so once the small coins add up to ten tens, they count as one dollar. Example: two 50c coins make ten tens, which is exactly $1; five 20c coins also make $1, and so do ten 10c coins. Remember these exchanges, and counting money and giving change become much easier. A common mistake is thinking 10c equals $1, or that five 10c coins make $5; in fact 10c is only one tenth of a dollar, and ten of them together make $1.
  3. Step 3: Count the moneyWhen counting money, put the same coins together first, then add one kind at a time, starting from the biggest value. Example: a $5 coin, a $2 coin and three 10c coins: first 5 + 2 = 7 dollars, then add 30c, and the total is $7 and 30c. Counting big money first and small money second keeps everything clear even when there are many coins. A common mistake is mixing different coins and misreading values, for example taking 20c for $2; so read the value aloud as each coin is counted and check carefully.
  4. Step 4: Paying for thingsWhen buying something, if the money paid is more than the price, the shop returns the extra part, and this is called change. Example: a bun costs $3; you pay with a $10 note, and 10 is greater than 3, so the shop returns $7. If the price equals what you pay, say a $10 thing paid with a $10 note, no change is needed. Before paying, estimate the price and check whether the money you bring is enough. A common mistake is swapping the price and the payment and trying to take the bigger from the smaller; the sum must always take the smaller away from the bigger.
  5. Step 5: Count the changeTo work out the change, take the price away from the money paid, and the answer is the amount to return. Example: pay $10 for a $3 bun and 10 - 3 = 7, so the change is $7; pay $5 for a $2 drink and 5 - 2 = 3, so the change is $3. After working it out, check by adding the price and the change back to see whether they equal what you paid: 3 + 7 = 10, and only then take the money. A common mistake is pocketing the change without checking; the habit of adding back keeps us from losing money.
  6. Step 6: Check you have enoughBefore buying, count your own money first: you can afford the thing only when your money is greater than or equal to the price; if it is smaller, you cannot buy it. Example: you want an $8 ball but have only $5; 5 is less than 8, so the money is not enough. With $8 or more, you can buy it, and paying $10 for the $8 ball brings back $2 in change. A common mistake is remembering the price but forgetting to count your own money, and finding out in the shop that it is not enough; so count the money before leaving home.

4Diagrams Diagrams

香港貨幣 Hong Kong money$1$2$5$10一元兩元五元十元$20$50$100二十元五十元一百元硬幣 coins · 紙幣 notes購物:價錢 − 付款 = 找續 change;10 元買 7 元貨品,找 3 元
Fig. 1: Hong Kong money

5Worked example Example

Example: a box of crayons costs $6. You pay with a $10 note. How much change should the shop return?

  1. Look at the price first: the crayons cost $6; this is what we must pay.
  2. Look at what we paid: we gave a $10 note, and 10 is greater than 6, so there is change.
  3. Write the sum: take the price away from what we paid, 10 - 6 = 4.
  4. Get the answer: 10 - 6 = 4, so the shop should return $4.
  5. Check: 6 + 4 = 10; price plus change equals the note, so the working is right.
  6. Answer: The shop should return $4. Because the crayons cost $6 and we paid $10, 10 - 6 = 4; adding $6 and $4 back gives $10, exactly the note we paid.

6Common mistakes Mistakes

✗ Treating 10c as $1
✓ 10c is 0.1 dollar; ten 10c coins make $1
✗ Adding to find change
✓ Change = paid - price; use subtraction
✗ Missing a coin when counting
✓ Sort the coins, count them one by one, then add
✗ Thinking notes are always bigger
✓ A $10 coin and a $10 note are both worth $10

7Quick check Quick check

Q1How many 10c coins make $1?

Q2A ball costs $8; pay $10; change?

Q3Two 50c coins equal?

Q4$5 + $2 = ?

Q5Want an $8 item with $5 only. Enough?

8Recap Recap

  • HK coins: 10c, 20c, 50c, $1, $2, $5, $10.
  • $1 = 100 cents (ten 10c).
  • Count money by adding each coin.
  • Change = paid - price.
  • Check you have enough before buying.

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