用简便方法计算: ①3-12/13-11/23 ②7/16-(3/16+1/9)
问题描述:
用简便方法计算: ①3-12/13-11/23 ②7/16-(3/16+1/9)
急就急
答
①3-12/23-11/23
=3-(12/23+11/23)
=3-1
=2
②7/16-(3/16+1/9)
=7/16-3/16-1/9
=4/16-1/9
=1/4-1/9
=5/36