Unit 8
Akal Pintar
Gunakan ketiga-tiga kad sekali sahaja:
□ − □ + □ = 218
分数卡填空 = isi kad pecahan
三张卡各用一次，放进 □ − □ + □ 里，使结果等于 2又1/8。可以先想：结果比 2 大，可以先试把最大的卡 2又1/2 放在最前面，再试另外两张卡的位置；其他排法也要检查，因为答案可能不止一种排法。
例子：卡 1/2、1/4、2，要得 1又3/4：2 − 1/2 + 1/4 = 1又3/4。
注意：每次试完都要统一分母算一算。
fraction card puzzle = isi kad pecahan
Use each of the three cards once in □ − □ + □ so that the answer is 2 1/8. Think first: the answer is more than 2, so try the biggest card, 2 1/2, first; then try the other two cards in the other places. Check other arrangements too, because more than one may work.
Example: with cards 1/2, 1/4 and 2, to get 1 3/4: 2 − 1/2 + 1/4 = 1 3/4.
Watch out: work out each try with a common denominator.
Cuba dua susunan
212 di depan
Tukar semua kepada perlapan
248 − 58 + 28 = 218 ✔
248 − 28 + 58 = 278 ✘
248 − 28 + 58 = 278 ✘
试两种排法 = cuba dua susunan
都换成八分之几：2又1/2 = 2又4/8，1/4 = 2/8。第一种：2又4/8 − 5/8 = 1又7/8，再加 2/8 = 2又1/8，正好。第二种：2又4/8 − 2/8 = 2又2/8，再加 5/8 = 2又7/8，不对。所以答案是 2又1/2 − 5/8 + 1/4。
例子：减去较大的数、加上较小的数，结果会比较小。
注意：统一分母后再比较，才不会看错。
try two arrangements = cuba dua susunan
Change everything into eighths: 2 1/2 = 2 4/8 and 1/4 = 2/8. First try: 2 4/8 − 5/8 = 1 7/8, plus 2/8 = 2 1/8, which is right. Second try: 2 4/8 − 2/8 = 2 2/8, plus 5/8 = 2 7/8, which is wrong. So the answer is 2 1/2 − 5/8 + 1/4.
Example: taking away the bigger card and adding the smaller one gives a smaller answer.
Watch out: compare only after using a common denominator.
Cuba
Kad: 13, 16, 2. Susunan manakah memberi 216?
逐个计算 = kira setiap susunan
每个选项都用同样的步骤检查：把三分之一换成六分之几，整数 2 写成“1又6/6”方便借位；然后从左到右，按照选项里的加减号一步一步算，看结果是不是 2又1/6。
例子：卡 1/2、1/4、3，排成 3 − 1/4 + 1/2 = 3又1/4；排成 3 − 1/2 + 1/4 = 2又3/4。
注意：同样三张卡，减去哪一张、加上哪一张，结果就不同，所以要看清楚每个符号后面是哪张卡。
work out each arrangement = kira setiap susunan
Check every choice the same way: write 1/3 in sixths, write 2 as 1 6/6 so you can borrow, then follow the signs in that choice from left to right and see whether you reach 2 1/6.
Example: with cards 1/2, 1/4 and 3, 3 − 1/4 + 1/2 = 3 1/4, but 3 − 1/2 + 1/4 = 2 3/4.
Watch out: with the same three cards, which card is subtracted and which is added changes the result, so read the sign in front of each card.
Ringkasan