第1个回答 2020-03-06
67×53-63×43
=67×10+67×43-63×43
=670+(67-63)×43
=670+172
=842
或:
67×53-63×43
=4×53+63×53-63×43
=212+63×(53-43)
=212+630
=842
第2个回答 2020-03-06
=(53+10)×57-53×(57+10)
=53×57+570-53×57-530
=40
第3个回答 2020-03-06
57×63-53×67
=(60-3)(60+3)-(60-7)(60+7)
=60²-3²-(60²-7²)
=3600-9-(3600-49)
=3600-9-3600+49
=40