"则古昔斋算学"是清代李善兰撰写的天文,数学著作集,共十三种二十四卷.包括"方圆阐幽"一卷,((弧矢启秘"二卷,"对数探源"二卷,"垛积比类"四卷,"四元解"二卷,"麟德术解"三卷,"椭圆正术解"二卷,"椭圆新术"一卷,"椭圆拾遗"三卷,"火器真诀"一卷,"对数尖锥变法释"一卷,"级数回求"一卷,"天算或问"一卷.1867年,在曾国藩的资助下,李善兰在南京刊刻出版了这一著作集,即金陵刊本.此外,该书还有光绪八年(1882)江宁藩署刊本,同文馆聚珍本及上海积山书局石印本等. [1]