Question

小学数学题详细求解！！！！

用递等式解答啊！！

9.75+99.75+999.75+9999.75=？

1989乘1999-1988乘2000=?

1842+290除58乘32=？

Answer 1

是简便计算吧

9.75+99.75+999.75+9999.75
=10-0.25+100-0.25+1000-0.25+10000-0.25
=11110-1
=11109

1989乘1999-1988乘2000
=1989×（2000-1）-1988×2000
=1989×2000-1989-1988×2000
=（1989-1988）×2000-1989
=11

1842+290除58乘32
=1842+290÷29÷2×32
=1842+10÷2×32
=1842+160
=2002

Answer 2

9.75+99.75+999.75+9999.75
=10-0.25+100-0.25+1000-0.25+10000-0.25
=11110-1
=11109
1989x1999-1988x2000
=1989x(2000-1)-(1989-1)x2000
=1989x2000-1989-1989x2000+2000
=2000-1989
=11
1842+290/58x32
=1842+5x32
=1842+160
=2002

Answer 3

9.75+99.75+999.75+9999.75
=(10-0.25)+(100-0.25)+(1000-0.25)+(10000-0.25)
=(10+100+1000+10000)-0.25×4
=11110-1
=11109

1989乘1999-1988乘2000
=1989×（2000-1）-（1989-1×2000）
=1989×2000-1989-1989×2000+2000
=2000-1989
=11

1842+290除58乘32
=1842+5×32
=1842+160
=2002

Answer 4

1、9.75+99.75+999.75+9999.75
=(10-0.25)+(100-0.25)+(1000-0.25)+(10000-0.75)
=10+100+1000+10000-0.25×4
=11110-1
=11109
2、1989×1999-1988×2000
=1989×1999-1988×（1999+1）
=1989×1999-1988×1999-1988
=（1989-1988）×1999-1988
=1999-1988
=11
3、1842+290÷58×32
=1842+290÷29÷2×32
=1842+(290÷29)×(32÷2)
=1842+10×160
=1842+160
=2002

Answer 5

9.75+99.75+999.75+9999.75
=10+100+1000+10000-0.25×4
=11110-1
=11109

1989×1999-1988×2000
=1989×（2000-1)-1988×2000
=1989×2000-1988×2000-1989
=2000×（1989-1988)-1989
=2000-1989
=11

1842+290÷58×32
=1842+290÷29÷2×32
=1842+10×32÷2
=1842+10×16
=1842+160
=2002

Answer 6

1. 9.75+99.75+999.75+9999.75
=(10-0.25)+（1000-0.25）+（1000-0.25）+（10000-0.25）
=10+100+1000+10000-1
=11110-1
=11109

2.1989*1999-1988*2000
=1989*（2000-1）-1988*2000
=1989*2000-1989-1988*2000
=（1989-1988）*2000-1989
=2000-1989
=11

3.1842+290/58*32
=1842+（290/58）*32
=1842+5*32
=1842+160
=2002