Mathematics notes, unit 4
Money
Textbook Mathematics Year 1 (DLP), Textbook Part 1 and Part 2, pages Part 2, 11–30
What this chapter covers
- You can name coins (5, 10, 20 and 50 sen) and notes (RM1, RM5 and RM10) and say their value (4.1.1, 4.1.2)
- You can find the value of some coins by counting on (4.1.2)
- You can swap money for other money of the same value (4.1.3)
- You can name ways to get money and keep a simple record (4.2.1, 4.2.2)
- You can add and subtract money, and find the amount left or the change (4.3.1)
4.1Recognise money and its value
We use money to buy things. Money has coins and notes. Every coin and note shows a number. The number tells its value.
sen is for small amounts. Ringgit (RM) is for bigger amounts. RM1 = 100 sen.
| Money | Say it |
|---|---|
| 5 sen | five sen |
| 20 sen | twenty sen |
| RM1 | one ringgit |
| RM6 | six ringgit |
Count on to find the total
Start with the biggest coin. Then count on.
Based on the Year 1 textbook, Part 2, page 14.
Worked example: 20 sen and 10 sen
Say 20 sen. Count on 10 more: 30 sen.The value is 30 sen.
Look at the word after the number. 50 sen is not the same as RM50.
What is the value of one 20 sen coin, one 10 sen coin and one 5 sen coin?
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20 sen, 30 sen, 35 sen. The value is 35 sen.
Swap money for the same value
You can swap money for other money that has the same value. A machine may not take a 5 sen coin, so you swap it.
Same value
10 sen + 10 sen = 20 sen20 sen + 20 sen + 10 sen = 50 sen
100 sen = RM1
There is more than one way. 20 sen can also be 10 sen + 5 sen + 5 sen.
Which is the same as 20 sen: 10 sen + 5 sen, or 10 sen + 10 sen?
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10 sen + 10 sen = 20 sen. 10 sen + 5 sen is only 15 sen.
4.2Get money and record money
We get money from pocket money, duit raya, gifts and from selling things. We should save some money and spend it wisely.
| Date | Money from | Save | Spend |
|---|---|---|---|
| 10 March | Granny, RM10 | RM5 | RM5, story book |
A table of money you get and money you spend helps you remember.
4.3Add and subtract money
Add: 50 sen + 30 sen
Count on: 50 sen, 60 sen, 70 sen, 80 sen.The total is 80 sen.
Subtract: 80 sen − 70 sen
Fara has 80 sen. She buys a toy for 70 sen.80 sen − 70 sen = 10 sen. She has 10 sen left.
Subtract: RM10 − RM4
Saiful has RM10 and gives RM4. Count back from RM10: RM9, RM8, RM7, RM6.RM10 − RM4 = RM6 left.
The change is the money the shop gives back to you. Change = the money you pay − the price.
Find the change
A bun is 60 sen. Najwa pays RM1 (100 sen).100 sen − 60 sen = 40 sen. The change is 40 sen, or four 10 sen coins.
Check the unit. Do not mix sen and RM in one sum. RM1 is 100 sen.
Kim has RM5. He buys a pen for RM2. How much money is left?
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RM5 − RM2 = RM3.
Summary
- Coins: 5 sen, 10 sen, 20 sen and 50 sen. Notes: RM1, RM5 and RM10.
- RM1 = 100 sen.
- Count on from the biggest coin to find the total.
- 20 sen = 10 sen + 10 sen. Money can be swapped for the same value.
- Add to find the total. Subtract to find what is left, the difference or the change.