Question

6道奥数题　　1．50×84/89＋46*42/89+84*26/89

1.50×84/89＋46*42/89+84*26/89 2.13又 4/19+86又 15/19*0.25+0.625*86又 15/19+86又 15/19*0.125　　　　　3．77*1/8+7/8*23又 10/13+7/13*3/8

Answer 1

1.50×84/89＋46*42/89+84*26/89
=50×84/89+23×84/89+84×26/89
=84/89(50+23+26)
=84*99/89
=8316/89

2.13又 4/19+86又 15/19*0.25+0.625*86又 15/19+86又 15/19*0.125
=13又 4/19+86又 15/19(*0.25+0.625+0.125)
=13又 4/19+86又 15/19*1
=13+86+4/19+15/19
=99+1
=100

3．77*1/8+7/8*23又 10/13+7/13*3/8
=11*7/8+7/8*23又 10/13+7/8*3/13
=7/8(11+23+10/13+3/13)
=7/8*(35)
=245/8

Answer 2

50×84/89＋46*42/89+84*26/89
=（50*2*42+23*2*42+84+26）/89
=（50*84+23*84+84*26）/89
=（50+23+26）/89
=84*99/89
=8316/89
第二题用乘法分配律，可以把86又 15/19看做公共的因数提取出来，先计算86又 15/19*0.25+0.625*86又 15/19+86又 15/19*0.125　再加13又 4/19