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代入 = gantikan 我们不知道 Puan Lim 原来有多少钱（R），也不知道第一次花了多少（S），但知道 R − S 剩下多少。把 R − S 换成这个值，再减去第二次花的钱。两个都是整千时，可以先减千位前面的数字，再补回三个 0。 例子：若 R − S = 10 000，那么 R − S − 3 000 = 10 000 − 3 000 = 7 000。 注意：第二次是“用掉”钱，要减，不是加；答案记得写 RM。

substitute = gantikan We do not know Puan Lim's starting money (R) or her first spending (S), but we know R − S. Replace R − S with that value, then take away the second spending. With whole thousands you can subtract the thousands digits and put the three zeros back. Example: if R − S = 10 000, then R − S − 3 000 = 7 000. Watch out: spending more means subtract, not add, and write RM in the answer.

代入再减 = gantikan, kemudian tolak 水箱原来的水量 G 和第一次用掉的 H 都不知道，但 G − H 已经知道。把 G − H 换成这个值，再减去第二次用掉的水。用竖式从个位减起，千位不够减时要向万位借。 例子：若 G − H = 20 400，那么 G − H − 1 200 = 20 400 − 1 200 = 19 200。 注意：借位以后万位要少 1；百位也要仔细减，答案记得写单位 ℓ。

substitute, then subtract = gantikan, kemudian tolak We do not know G or H, but we know G − H. Replace it with that value and take away the second amount of water. Subtract in columns from the ones, borrowing from the ten thousands when the thousands are not enough. Example: if G − H = 20 400, then G − H − 1 200 = 19 200. Watch out: after borrowing the ten thousands are 1 less, subtract the hundreds carefully, and write the unit ℓ.

减去自己 = tolak nombor yang sama 先把 P − Q 这一整块换成它的值；再看后面要减去的数，正好和这个值一样。一个数减去和它一样大的数，会剩下多少？想一想：有 8 颗糖，全部送出 8 颗，还剩几颗？ 例子：7 250 − 7 250 就像有 7 250 张贴纸，全部送出去，一张也不留。 注意：减去一样的数，不是把它加倍；这一题的式子是减号。

take a number from itself = tolak nombor yang sama Replace the block P − Q with its value, then notice that the number being taken away is exactly the same. What is left when you take a number away from itself? Think of giving away all 8 sweets from 8. Example: 7 250 − 7 250 is like having 7 250 stickers and giving every one of them away. Watch out: taking away the same number does not double it; the sign here is minus.