79x25+22x25-25的简便计算 79×25+22×25-25简算?
79\u4e5825+22\u4e5825-25 \u7b80\u4fbf\u8ba1\u7b9779X25+22X25-25
=79X25+21X25
=\uff0879+21\uff09X25
=100X25
=2500
\u8fd0\u7528\u4e58\u6cd5\u7ed3\u5408\u5f8b\u8fdb\u884c\u7b80\u7b97\uff0c\u5373
79\u00d725+22\u00d725-25
=79\u00d725+22\u00d725-25\u00d71
=25\u00d7\uff0879+22-1\uff09
=25\u00d7100
=2500
图
利用乘法结合律提取25。
乘法分配律为:两个数的和与一个数相乘,先将它们与这个数分别相乘,再相加,积不变.即:(a+b)×c=a×c+b×c.反过来则:a×c+b×c=(a+b)×c79×25+22×25-25= 25× (79+22-1)= 25×100=2500
=(79+22-1)×25
=100×25
=2500
绛旓細锛79+21锛壝25 =100脳25 =2500 濡傚府鍒颁綘锛岃鐐归噰绾筹紝璋㈣阿
绛旓細鍥炵瓟锛=25x(79+22-1) =25x100 =2500
绛旓細鍥
绛旓細79脳25+22脳25-25 =锛79+22-1锛壝25 =100脳25 =2500 浣犲ソ锛屾湰棰樺凡瑙g瓟锛屽鏋滄弧鎰忥紝璇风偣鍙充笂瑙掆滈噰绾崇瓟妗堚濓紝鏀寔涓涓嬨
绛旓細鍘熷紡绛変簬 25脳锛79+22-1锛=25脳100 =2500 鎵浠ュ師寮忕殑璁$畻缁撴灉涓2500.
绛旓細79脳25+22脳25-25绠绠 79X25+22X25-25 =79X25+21X25 =锛79+21锛塜25 =100X25 =2500 79脳25+22脳25-25鐢ㄨ劚寮忕畻鎬庝箞绠 瑙o細 79脳25+22脳25-25 =25脳(79+22-1) =25脳100 =2500 79脳25+22脳25-25鐨杩囩▼ 鍒╃敤涔樻硶瑙勫緥锛 79 脳 25 + 22 脳 25 - 25 = 25...
绛旓細绗竴涓笉鏄+锛屾槸X鍚 涓嬮潰鎸夌収鈥淴鈥濇潵璁$畻锛屽師寮=锛79+22-1锛X25 =锛101-1锛塜25 =100X25 =2500
绛旓細璇烽噰绾
绛旓細鍘熷紡=4鍙1/5脳(7鍙1/3-3鍙1/7)脳(-5/22)=21/5脳(-5/22)脳(22/3-22/7)=21/5脳(-5/22)脳22脳(1/3-1/7锛=-21脳(1/3-1/7)=-21脳1/3+(-21)脳(-1/7)=-7+3 =-4
绛旓細79x25鍗22x25涓25 =79x25鍗22x25-25x1 =(79鍗22鍗1)x25 =100x25 =2500 鎴戦兘鍙戝崐澶╀簡