21×36+36×21=?72×26 +36×48简便方法用简便方法怎么算

来源:学生作业帮助网 编辑:作业帮 时间:2024/11/05 21:42:51

21×36+36×21=?72×26 +36×48简便方法用简便方法怎么算
21×36+36×21=?72×26 +36×48简便方法用简便方法怎么算

21×36+36×21=?72×26 +36×48简便方法用简便方法怎么算
① 21×36+36×21
=36×21+21×4+21×32
=21×(4+36)+21×32
=21×40+21×32
=21×40+21×30+21×2
=21×(40+30)+42
=21×70+42
=1470+42
=1512
② 72×26 +36×48
=2×36×26+36×48
=36×52+36×48
=36×(52+48)
=36×100
=3600
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