15的倍數20243613391815和20的公倍數24和3613和3918和24 ... 15倍數:30.45.60.75.90 20倍數:40.60.80.100.120 24倍數:48.72.96.120.144 36倍數:72.108.144.180.216 13倍數:26.39.52.65.78 39倍數:78.117.156.195.234
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