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看个位 = lihat digit sa 这题要从四样东西中找出三样，价钱加起来等于题目给的总数。先看个位：总数的个位是零，因此挑出来的三个个位加起来必须是零或十。用这个条件先排除一些组合，剩下的再用竖式算出总数，和题目比较。 例子：价钱 RM305、RM410、RM125、RM260，要凑 RM840 → 个位 5 + 5 + 0 = 10，试 305 + 125 + 410 = 840，符合。 注意：个位符合的组合可能不止一个，一定要算出完整的总数才能确定。

look at the ones = lihat digit sa Choose three of the four items whose prices add up to the given total. Start with the ones digits: the total ends in 0, so the three chosen ones digits must add up to 0 or 10. Use this to rule out some groups, then add the rest in columns and compare. Example: prices RM305, RM410, RM125 and RM260, target RM840; ones 5 + 5 + 0 = 10, and 305 + 125 + 410 = 840, which fits. Watch out: more than one group can fit the ones digit, so always work out the full total.

求方框里的金额 = cari nilai ketiga 三个金额加起来等于总数，其中两个已经知道。先把已知的两个加起来，再用总数减去这个和，剩下的就是方框。最后把三个金额加回去检查。 例子：RM400 + RM300 + □ = RM1 000，先算 RM700，再算 RM1 000 − RM700 = RM300。 注意：已知两个金额的和只是第一步，不是方框的值。

find the third amount = cari nilai ketiga Three amounts make the total and two of them are known. Add the two known amounts, then subtract that sum from the total; what is left is the box. Add all three back to check. Example: RM400 + RM300 + □ = RM1 000; first RM700, then RM1 000 − RM700 = RM300. Watch out: the sum of the two known amounts is only the first step, not the value of the box.