| 用递等式计算. ①207-198÷9 ②89-13×6+65 ③15×27-3000÷25 ④(145-121)×18÷27 ⑤(85+420)÷(24-19) |
| (1)207-198÷9 =207-22 =22; (2)89-13×6+65 =89-78+65 =11+65 =76; (3)15×27-3000÷25 =405-120 =285; (4)(145-121)×18÷27 =24×18÷27 =432÷27 =16; (5)(85+420)÷(24-19) =505÷5 =101. |
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