简便计算464-545+99+34553.7-(54.3-16.3)-5.7947+(372-447)-5729999*9999402*158888/7777/1111*1111146*83+18*146-1461025/25987654321*1235-987654321*12341+2+3+4.+99+100

Question

简便计算
464-545+99+345
53.7-(54.3-16.3)-5.7
947+(372-447)-572
9999*9999
402*15
8888/7777/1111*1111
146*83+18*146-146
1025/25
987654321*1235-987654321*1234
1+2+3+4.+99+100

Answer 1

464-545+99+345=464+(345-545)+99
=464-200+100-1
=463-100
=563
53.7-(54.3-16.3)-5.7=(53.7-5.7)-(54.3-16.3)
=(53-5)-(54-16)
=(53-54)+16-5
=9-1
=8
947+(372-447)-572=(947-447)+(372-572)
=500-200
=300
9999×9999=(10000-1)×9999
=99990000-9999
=99990000-10000+1
=99980000+1
=99980001
402×15=(400+2)×15
=6000+30
=6030
8888÷777÷1111×1111=(8888÷7777)×(1111÷1111)
=8/7
146×83+18×146-146=146×(83+18-1)
=146×(83+17)
=146×100
=14600
1025÷25=(1000+25)÷25
=1000÷25+25÷25
=40+1
=41
987654321×1235-987654321×1234=987654321×(1235-1234)
=987654321
1+2+3+4+.+99+100=[(1+2+3+4+.+99+100)+(1+2+3+4+.+99+100)]÷2
=[(100+99+.+3+2+1)+(1+2+3+4+.+99+100)]÷2
=[(100+1)+(99+2)+(98+3)+……+(3+98)+(99+2)+(100+1)]÷2
=100×101÷2
=10100÷2
=5050