Unit 4
Akal Pintar
RM36 500 − RM4 275.50 = □ − RM12 318.25
Berapakah nilai yang diwakili oleh □?
等号两边相等 = dua belah sama nilai
等号的意思是左边和右边的值一样。左边两个金额都知道，可以先算出来；右边是一个未知数减去已知金额。所以先算左边，再想：什么金额减去一万两千三百一十八令吉二十五仙，会得到左边的答案。
例子：RM10 − RM4 = □ − RM2 → 左边 RM6，□ = RM8。
注意：等号不是“答案在这里”，而是两边一样多。
both sides are equal = dua belah sama nilai
The equals sign means the left side and the right side have the same value. Both amounts on the left are known, so work it out first. The right side is an unknown minus a known amount. Then ask: what amount minus RM12 318.25 gives the left side?
Example: RM10 − RM4 = □ − RM2: the left side is RM6, so □ = RM8.
Watch out: the equals sign means both sides are the same, not just 'the answer goes here'.
Cara
Kira sebelah kiri, kemudian tambah
□ = sebelah kiri + RM12 318.25
Langkah 1: kiri
| RM | 3 | 6 | 5 | 0 | 0 | . | 0 | 0 | |
| − | RM | 4 | 2 | 7 | 5 | . | 5 | 0 | |
| RM | 3 | 2 | 2 | 2 | 4 | . | 5 | 0 |
Langkah 2: □
| RM | 3 | 2 | 2 | 2 | 4 | . | 5 | 0 | |
| + | RM | 1 | 2 | 3 | 1 | 8 | . | 2 | 5 |
| RM | 4 | 4 | 5 | 4 | 2 | . | 7 | 5 |
□ = RM44 542.75
先算左边再加 = kira kiri, kemudian tambah
左边：三万六千五百减四千二百七十五令吉五十仙，得三万二千二百二十四令吉五十仙。右边是□减一万两千三百一十八令吉二十五仙也要等于这个数，所以□等于左边的答案加回一万两千三百一十八令吉二十五仙，得四万四千五百四十二令吉七十五仙。
例子：RM50 − RM20 = □ − RM5 → □ = RM30 + RM5 = RM35。
注意：□在减号前面，所以要用加法求它。
work out the left, then add = kira kiri, kemudian tambah
Left side: RM36 500 − RM4 275.50 = RM32 224.50. The right side □ − RM12 318.25 must equal this, so □ = RM32 224.50 + RM12 318.25 = RM44 542.75.
Example: RM50 − RM20 = □ − RM5, so □ = RM30 + RM5 = RM35.
Watch out: □ comes before the minus sign, so add to find it.
Semak
RM18 000 − RM3 750.40 = □ − RM6 125.60
Aina kata □ = RM8 124. Betulkah?
检查别人的答案 = semak jawapan orang lain
要判断爱娜说得对不对，先算出左边的值，再把她的数放进右边的方框，算一算右边等于多少。两边一样才对；不一样，就想一想方框应该变大还是变小，右边才会等于左边。方框在减号前面，方框越大，右边就越大。
例子：RM50 − RM20 = □ − RM5，有人说 □ = RM25，右边 RM25 − RM5 = RM20，比左边 RM30 小，所以方框要更大。
注意：方框在减号前面时，求它要用加法；用减法去求，常常会得到太小的数。
check someone's answer = semak jawapan orang lain
To decide whether Aina is right, first work out the left side. Then put her number in the box and work out the right side. If both sides match, she is right; if not, think about whether the box must be bigger or smaller to make the sides equal. The box comes before a minus sign, so a bigger box makes the right side bigger.
Example: RM50 − RM20 = □ − RM5; someone says □ = RM25, but RM25 − RM5 = RM20, less than RM30, so the box must be bigger.
Watch out: when the box comes before the minus sign, find it by adding; subtracting usually gives a number that is too small.
Ringkasan
Syabas!
kiri = kanan
Kira sebelah yang diketahui dahulu, kemudian cari □ supaya kedua-dua belah sama.
Latihan tambahan →