Unit 4
Darab Panjang
Lebar sebuah rumah teres ialah 6 m 35 cm.
Ada 4 buah rumah teres yang sama lebar dalam satu deret.
Berapakah panjang deretan rumah itu?
长度乘法 = darab panjang；一排 = satu deret
这一课学同一个长度重复好几次，一共多长。一间排屋宽 6 m 35 cm，一排有 4 间一样宽的排屋，整排有多长，就是 6 m 35 cm × 4。乘法是同一个长度连加几次的快捷方法。
例子：一块砖长 20 cm，排 3 块，一共 20 × 3 = 60 cm。
注意：乘完以后，cm 满 100 也要换成 m。
multiplying length = darab panjang; one row = satu deret
In this unit one length repeats several times and we find the total. A terrace house is 6 m 35 cm wide and there are 4 houses of the same width in a row; the length of the row is 6 m 35 cm × 4. Multiplying is a short way of adding the same length again and again.
Example: a brick is 20 cm long, so 3 bricks laid end to end make 20 × 3 = 60 cm.
Watch out: after multiplying, centimetres that reach 100 must still change into metres.
Satu unit sahaja
125 cm × 4 · 23 m × 3
Darab seperti nombor biasa
cm
125 × 4 = 500 cm
= 5 m
= 5 m
m
23 × 3 = 69 m
500 cm ÷ 100 = 5 m
单名数乘法 = darab satu unit
只有一个单位时，就像普通乘法：125 × 4，个位 5 × 4 = 20 写 0 进 2，十位 2 × 4 + 2 = 10 写 0 进 1，百位 1 × 4 + 1 = 5，得 500 cm，刚好是 5 m。23 m × 3 = 69 m，m 是大单位，不用再换。
例子：150 cm × 2 = 300 cm = 3 m；12 m × 4 = 48 m。
注意：乘出来的 cm 是整百时，可以换成米，让答案更简单。
multiplying one unit = darab satu unit
With only one unit, multiply like ordinary numbers. For 125 × 4: ones 5 × 4 = 20, write 0 and carry 2; tens 2 × 4 + 2 = 10, write 0 and carry 1; hundreds 1 × 4 + 1 = 5, giving 500 cm, which is exactly 5 m. 23 m × 3 = 69 m, and metres are the big unit, so nothing more changes.
Example: 150 cm × 2 = 300 cm = 3 m; 12 m × 4 = 48 m.
Watch out: when the centimetres come out as whole hundreds, you can change them into metres for a simpler answer.
Cuba
214 m × 3 = ?
| m | |
|---|---|
| 214 | |
| × | 3 |
| ? |
三位数乘一位数 = darab tiga digit
个位 4 × 3 = 12，写 2 进 1；十位 1 × 3 = 3，加进位 1 得 4；百位 2 × 3 = 6。答案 642 m。
例子：132 m × 2 = 264 m。
注意：632 m 漏了个位进上去的 1；217 m 是把乘号当成加号。
three digits times one digit = darab tiga digit
Ones: 4 × 3 = 12, write 2 and carry 1. Tens: 1 × 3 = 3, plus the carried 1 makes 4. Hundreds: 2 × 3 = 6. The answer is 642 m.
Example: 132 m × 2 = 264 m.
Watch out: 632 m forgets the carry from the ones, and 217 m treats the times sign as a plus sign.
m dan cm
2 m 15 cm × 3
Darab cm, kemudian darab m
| m | cm | |
|---|---|---|
| 2 | 15 | |
| × | 3 | |
| 6 | 45 |
cm: 15 × 3 = 45 · m: 2 × 3 = 6
复名数乘法 = darab m dan cm
乘数要乘 cm，也要乘 m，两栏都要乘。先乘 cm：15 × 3 = 45，没有到 100，直接写 45。再乘 m：2 × 3 = 6。答案 6 m 45 cm。
例子：1 m 20 cm × 4 → 20 × 4 = 80 → 1 × 4 = 4 → 4 m 80 cm。
注意：只乘 cm 不乘 m（得 2 m 45 cm）是常见错误。
multiplying m and cm = darab m dan cm
The multiplier goes into both columns: the cm and the m. Multiply the centimetres first: 15 × 3 = 45, which is below 100, so write 45. Then multiply the metres: 2 × 3 = 6. The answer is 6 m 45 cm.
Example: 1 m 20 cm × 4 → 20 × 4 = 80 → 1 × 4 = 4 → 4 m 80 cm.
Watch out: multiplying only the cm and not the m, which gives 2 m 45 cm, is a common slip.
Kumpul 100 sebagai 1 m
6 m 35 cm × 4
cm dahulu, kemudian m
140 cm = 100 cm + 40 cm = 1 m 40 cm → tulis 40, bawa 1
积满 100 进位 = kumpul 100 sebagai 1 m
先乘 cm：35 × 4 = 140 cm。把 140 拆成整百和零头：100 和 40。100 cm 就是 1 m，进到 m 栏；40 cm 留在 cm 栏。再乘 m：6 × 4 = 24，加上进来的 1 得 25。整排排屋长 25 m 40 cm。
例子：2 m 60 cm × 2 → 60 × 2 = 120 = 1 m 20 cm → 4 + 1 = 5 → 5 m 20 cm。
注意：进位是先乘完 m 再加，不可以先加再乘。
packing 100 into 1 m = kumpul 100 sebagai 1 m
Multiply the centimetres first: 35 × 4 = 140 cm. Split 140 into a hundred and the rest: 100 and 40. The 100 cm is 1 m, which goes to the m column, and 40 cm stays in the cm column. Then the metres: 6 × 4 = 24, plus the carried 1 makes 25. The row of houses is 25 m 40 cm long.
Example: 2 m 60 cm × 2 → 60 × 2 = 120 = 1 m 20 cm → 4 + 1 = 5 → 5 m 20 cm.
Watch out: multiply the metres first and only then add the carry, never the other way round.
Cuba
3 m 45 cm × 3 = ?
| m | cm | |
|---|---|---|
| 3 | 45 | |
| × | 3 | |
| ? | ? |
cm 先乘 = darab cm dahulu
45 × 3 = 135 cm，135 − 100 = 35，写 35，进 1 m。m：3 × 3 = 9，加 1 得 10。答案 10 m 35 cm。
例子：2 m 50 cm × 3 → 50 × 3 = 150 → 写 50，进 1 → 6 + 1 = 7 → 7 m 50 cm。
注意：9 m 35 cm 拆出了 100 cm，却忘了把 1 m 加进 m 栏。
multiply the cm first = darab cm dahulu
45 × 3 = 135 cm; 135 − 100 = 35, so write 35 and carry 1 m. Metres: 3 × 3 = 9, plus 1 makes 10. The answer is 10 m 35 cm.
Example: 2 m 50 cm × 3 → 50 × 3 = 150 → write 50, carry 1 → 6 + 1 = 7 → 7 m 50 cm.
Watch out: 9 m 35 cm takes out the 100 cm but never adds the 1 m to the metre column.
Bawa lebih daripada 1
4 m 65 cm × 5
325 cm = 3 m 25 cm
| m | cm | |
|---|---|---|
| 3 | ||
| 4 | 65 | |
| × | 5 | |
| 23 | 25 |
65 × 5 = 325 cm = 3 m 25 cm → tulis 25, bawa 3
进 3 = bawa 3
cm 的积可能有好几个 100。65 × 5 = 325 cm，里面有 3 个 100，剩 25，所以 cm 栏写 25，进 3 m。再乘 m：4 × 5 = 20，加 3 得 23。答案 23 m 25 cm。
例子：1 m 50 cm × 4 → 50 × 4 = 200 = 2 m → cm 写 0 → 4 + 2 = 6 → 6 m。
注意：积是 325 时进 3，不是只进 1；看百位是几就进几。
carrying 3 = bawa 3
The cm product can hold several hundreds. 65 × 5 = 325 cm, which has three 100s with 25 left, so write 25 in the cm column and carry 3 m. Then the metres: 4 × 5 = 20, plus 3 makes 23. The answer is 23 m 25 cm.
Example: 1 m 50 cm × 4 → 50 × 4 = 200 = 2 m → write 0 cm → 4 + 2 = 6 → 6 m.
Watch out: a product of 325 means carrying 3, not just 1; the hundreds digit tells you how many to carry.
Cuba
1 m 80 cm × 6 = ?
| m | cm | |
|---|---|---|
| 1 | 80 | |
| × | 6 | |
| ? | ? |
进 4 = bawa 4
80 × 6 = 480 cm，里面有 4 个 100，剩 80，写 80，进 4 m。m：1 × 6 = 6，加 4 得 10。答案 10 m 80 cm。
例子：90 cm × 5 = 450 cm = 4 m 50 cm。
注意：7 m 80 cm 只进了 1；6 m 480 cm 还没把 400 cm 换成 4 m。
carrying 4 = bawa 4
80 × 6 = 480 cm, which holds four 100s with 80 left, so write 80 and carry 4 m. Metres: 1 × 6 = 6, plus 4 makes 10. The answer is 10 m 80 cm.
Example: 90 cm × 5 = 450 cm = 4 m 50 cm.
Watch out: 7 m 80 cm carries only 1, and 6 m 480 cm has not yet changed the 400 cm into 4 m.
Jawapan dalam cm
2 m 15 cm × 3 = ? cm
Semak dengan tambah berulang
6 m 45 cm = 645 cm
215 cm × 3 = 645 cm
Semak: 215 + 215 + 215 = 645 ✓
答案化成厘米 = jawapan dalam cm；用连加验算 = semak dengan tambah berulang
题目要 cm 的答案时，可以先算出 6 m 45 cm，再化成 600 + 45 = 645 cm；也可以一开始就把 2 m 15 cm 化成 215 cm，再乘 3。乘法就是连加，所以 215 + 215 + 215 = 645，可以用来检查。
例子：1 m 30 cm × 2 = 2 m 60 cm = 260 cm；130 + 130 = 260。
注意：化成 cm 时 m 要乘 100，6 m 45 cm 不是 645 m。
answer in cm = jawapan dalam cm; checking by repeated adding = semak dengan tambah berulang
When the question wants centimetres, you can first find 6 m 45 cm and then change it to 600 + 45 = 645 cm, or change 2 m 15 cm into 215 cm at the start and multiply by 3. Multiplying is repeated adding, so 215 + 215 + 215 = 645 is a good check.
Example: 1 m 30 cm × 2 = 2 m 60 cm = 260 cm, and 130 + 130 = 260.
Watch out: when changing to cm, multiply the metres by 100; 6 m 45 cm is 645 cm, not 645 m.
Cuba
Puan Lim memotong 5 helai kain. Setiap helai panjangnya 2 m 40 cm. Berapakah jumlah panjang kain itu?
五块布的总长 = jumlah panjang 5 helai kain
每块一样长，用乘法：2 m 40 cm × 5。cm：40 × 5 = 200 cm = 2 m，cm 栏写 0，进 2。m：2 × 5 + 2 = 12。答案 12 m。
例子：3 条绳子各 1 m 50 cm → 50 × 3 = 150 → 4 m 50 cm。
注意：10 m 40 cm 只乘了 m，cm 部分忘了乘 5。
the total length of 5 pieces = jumlah panjang 5 helai kain
Each piece is the same length, so multiply: 2 m 40 cm × 5. Centimetres: 40 × 5 = 200 cm = 2 m, so write 0 cm and carry 2. Metres: 2 × 5 + 2 = 12. The answer is 12 m.
Example: 3 ropes of 1 m 50 cm each → 50 × 3 = 150 → 4 m 50 cm.
Watch out: 10 m 40 cm multiplies only the metres and forgets to multiply the cm part by 5.
Padankan
Hasil darab panjang
配对乘积 = padankan hasil darab
50 × 2 = 100 cm = 1 m。1 m 25 cm × 4：25 × 4 = 100 cm = 1 m，cm 写 0，1 × 4 + 1 = 5，得 5 m。2 m 30 cm × 3：30 × 3 = 90，2 × 3 = 6，得 6 m 90 cm。3 m × 7 = 21 m。
例子：25 cm × 4 = 100 cm = 1 m。
注意：cm 的积刚好是 100 的时候，答案只剩整米。
matching products = padankan hasil darab
50 × 2 = 100 cm = 1 m. For 1 m 25 cm × 4: 25 × 4 = 100 cm = 1 m, so write 0 cm and 1 × 4 + 1 = 5, giving 5 m. For 2 m 30 cm × 3: 30 × 3 = 90 and 2 × 3 = 6, giving 6 m 90 cm. 3 m × 7 = 21 m.
Example: 25 cm × 4 = 100 cm = 1 m.
Watch out: when the cm product is exactly 100, only whole metres remain in the answer.
Ringkasan
Syabas!
darab cm → cukup 100, bawa ke m → darab m + bawa
Darab cm dahulu. Setiap 100 cm jadi 1 m dan dibawa ke lajur m. Darab m, kemudian tambah nombor yang dibawa.
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