Darab dan Bahagi Isi Padu Cecair

先除后乘 = bahagi dahulu, kemudian darab 食谱是四个人的分量，先求一个人要多少：九百毫升除以四。用长除法：九除以四得二余一，余一和十位的零合成十，除以四得二余二，再和个位的零合成二十，除以四得五，一个人二百二十五毫升。再求六个人：二百二十五乘六，等于一千三百五十毫升，满一千毫升是一升，所以是一升三百五十毫升。 例子：800 mℓ ÷ 5 × 2 = 160 mℓ × 2 = 320 mℓ。 注意：先找出“一份”，再求“几份”，这是先除后乘的意思。

divide first, then multiply = bahagi dahulu, kemudian darab The recipe serves 4 people, so first find one person's share: 900 mℓ ÷ 4. With long division: 9 ÷ 4 = 2 remainder 1; bring down 0 to make 10, ÷ 4 = 2 remainder 2; bring down 0 to make 20, ÷ 4 = 5. One person needs 225 mℓ. For 6 people, 225 × 6 = 1 350 mℓ; 1 000 mℓ is 1 ℓ, so that is 1 ℓ 350 mℓ. Example: 800 mℓ ÷ 5 × 2 = 160 mℓ × 2 = 320 mℓ. Watch out: find one share first, then several shares; that is what dividing before multiplying means.

两种方法 = dua cara 先把五升化成五千毫升。方法一按次序先除：五千除以六除不尽，会有余数，不方便继续算。方法二先乘后除：五千乘三得一万五千，再除以六，刚好得两千五百毫升。乘法和除法连在一起时，先乘再除，答案一样；当先除除不尽时，先乘常常会更方便。 例子：1 ℓ ÷ 3 × 6 → 1 000 ÷ 3 除不尽；1 000 × 6 = 6 000，6 000 ÷ 3 = 2 000 mℓ。 注意：一升是一千毫升，化单位时要乘一千，不是乘一百。

two methods = dua cara First change 5 ℓ into 5 000 mℓ. Method 1 divides first, in order: 5 000 ÷ 6 does not divide exactly and leaves a remainder, which is awkward to carry on with. Method 2 multiplies first: 5 000 × 3 = 15 000, then ÷ 6 gives exactly 2 500 mℓ. When × and ÷ come together, multiplying first gives the same answer, and it is often easier when dividing first is not exact. Example: 1 ℓ ÷ 3 × 6 → 1 000 ÷ 3 is not exact; 1 000 × 6 = 6 000 and 6 000 ÷ 3 = 2 000 mℓ. Watch out: to change litres into millilitres multiply by 1 000, not by 100.

化单位再除乘 = tukar unit, bahagi, darab 八升一百二十毫升先化成毫升：八千加一百二十，是八千一百二十毫升。除以四：八除以四得二，一除以四不够，商写零，十二除以四得三，零除以四得零，商是两千零三十。商里的零要写上，不能跳过。再乘三得六千零九十毫升。最后化回升和毫升：六千毫升是六升，剩九十毫升，写成六升九十毫升，毫升的百位是零。 例子：6 ℓ 240 mℓ ÷ 3 × 2 → 6 240 ÷ 3 = 2 080 → 2 080 × 2 = 4 160 mℓ = 4 ℓ 160 mℓ。 注意：除到不够除的一位时，商要写零占位。

change units, then divide and multiply = tukar unit, bahagi, darab Change 8 ℓ 120 mℓ into millilitres: 8 000 + 120 = 8 120 mℓ. Divide by 4: 8 ÷ 4 = 2; 1 ÷ 4 is not possible, so write 0; 12 ÷ 4 = 3; 0 ÷ 4 = 0. The quotient is 2 030, and its zero must be written. Multiply by 3 to get 6 090 mℓ. Change back: 6 000 mℓ is 6 ℓ, leaving 90 mℓ, so it is 6 ℓ 90 mℓ with a zero in the hundreds of the mℓ. Example: 6 ℓ 240 mℓ ÷ 3 × 2 → 6 240 ÷ 3 = 2 080 → 2 080 × 2 = 4 160 mℓ = 4 ℓ 160 mℓ. Watch out: when a digit is too small to divide, write 0 in the quotient to hold its place.

找错 = cari kesilapan 阿明先乘的一步是对的：二升三百八十毫升乘三，毫升一千一百四十，进一升，得七升一百四十毫升。错在除的时候：七除以四得一，余三，他把余下的三升丢掉了，只用一百四十毫升除以四。正确做法：余下的三升化成三千毫升，加一百四十毫升，一共三千一百四十毫升，除以四得七百八十五毫升，结果一升七百八十五毫升。也可以一开始就全部化成毫升：七千一百四十除以四。 例子：2 × 2 ℓ 250 mℓ ÷ 3 → 4 ℓ 500 mℓ ÷ 3 → 1 ℓ 余 1 ℓ → 1 500 mℓ ÷ 3 = 500 mℓ → 1 ℓ 500 mℓ。 注意：升的余数不能丢，也不能直接写成毫升的余数。

find the mistake = cari kesilapan Amin's multiplying step is right: 3 × 2 ℓ 380 mℓ gives 1 140 mℓ, which regroups 1 ℓ, so 7 ℓ 140 mℓ. The mistake is in dividing: 7 ÷ 4 = 1 remainder 3, but he threw away the 3 ℓ left over and divided only the 140 mℓ. Correctly, the 3 ℓ left become 3 000 mℓ, plus 140 mℓ makes 3 140 mℓ, and ÷ 4 gives 785 mℓ, so the answer is 1 ℓ 785 mℓ. You could also change everything into millilitres at the start: 7 140 ÷ 4. Example: 2 × 2 ℓ 250 mℓ ÷ 3 → 4 ℓ 500 mℓ ÷ 3 → 1 ℓ remainder 1 ℓ → 1 500 mℓ ÷ 3 = 500 mℓ → 1 ℓ 500 mℓ. Watch out: a remainder of litres must not be dropped or copied as millilitres.

先乘后除 = darab, kemudian bahagi 先把“几升几毫升”化成毫升，再按次序计算：先乘，得到总量；再除，得到每一份。除完以后看看题目要的单位，这题要毫升，所以不用再化回升。 例子：3 × 1 ℓ 200 mℓ ÷ 4 → 3 600 mℓ ÷ 4 = 900 mℓ。 注意：每算完一步，都要写上单位，再看看下一步要做什么。

multiply, then divide = darab, kemudian bahagi Change the litres and millilitres into millilitres, then work in order: multiply to find the total, then divide to find one share. Check the unit wanted; here it is millilitres, so there is no need to change back to litres. Example: 3 × 1 ℓ 200 mℓ ÷ 4 → 3 600 mℓ ÷ 4 = 900 mℓ. Watch out: write the unit after every step, then decide what the next step is.

先除后乘 = bahagi, kemudian darab 先化成毫升，用长除法除以九，求出一份；再乘二，求出两份。最后把毫升化回“几升几毫升”：每一千毫升是一升，剩下的是毫升。 例子：12 ℓ 600 mℓ ÷ 4 × 3 → 12 600 ÷ 4 = 3 150 → 3 150 × 3 = 9 450 mℓ = 9 ℓ 450 mℓ。 注意：化回升和毫升时，要看清楚毫升部分每一个数字的位值。

divide, then multiply = bahagi, kemudian darab Change to millilitres, divide by 9 with long division to find one share, then multiply by 2 for two shares. Finally change the millilitres back to litres and millilitres: every 1 000 mℓ is 1 ℓ and the rest stay as mℓ. Example: 12 ℓ 600 mℓ ÷ 4 × 3 → 12 600 ÷ 4 = 3 150 → 3 150 × 3 = 9 450 mℓ = 9 ℓ 450 mℓ. Watch out: when changing back to ℓ and mℓ, check the place value of every digit in the mℓ part.