A-A+
(56+712+23)×481835×1920+225×1920-19204113×34+5
问题详情
( (1))(56+712+23)×485 6+ 7 12+ 2 3)×48
183 5× 19 20+2 2 5× 19 20- 19 20
411 3× 3 4+51 1 4× 4 5+61 1 5× 5 6
2001×1999 2000
1998÷19981998 1999 1 2+ 1 6+ 1 12+ 1 20+ 1 30+ 1 42+ 1 56.
参考答案
=56×48+712×48+23×48,
=40+28+32,
=100;
(2)1835×1920+225×1920-1920
=(1835+225-1)×1920,
=20×1920,
=19;
(3)4113×34+5114×45+6115×56
=(40+113)×34+(50+114)×45+(60+115)×56,
=40×34+43×34+50×45+54×45+60×56+65×56,
=30+1+40+1+50+1,
=123;
(4)2001×19992000
=(2000+1)×19992000,
=2000×19992000+1×19992000,
=1999+19992000,
=199919992000;
(5)1998÷199819981999
=19998÷1999×1998+19981999,
=1998×1999(1999+1)×1998,
=19992000;
(6)12+16+112+120+130+142+156.
=11×2+12×3+13×4+24×5+15×6+16×7+17×8
=1-12+12-13+13-14+…+17-18,
=78.考点: