小学六年级奥数（分数计算的技巧）

234468/123246
=（234 x 1002）/(123 x1002)
= 234/123
=78/41

51又2/3÷5/3+71又3/4÷7/4+91又4/5÷9/5
=155/3 x 3/5 + 231/4 x 4/7 + 459/5 x 5/9
= 31 + 33 +51
= 115

1又4/17*(2又2/3-3/4)+17又11/12÷17/21
=21/17*(8/3 – 3/4) + 215/12 * 21/17
=21/17*(215/12+8/3-3/4)
=21/17*24
=504/17

13又7/13-(4又1/4+3又7/13)-0.75
= 13又7/13-4又1/4-3又7/13-0.75
= 13又7/13-3又7/13-(0.75+4又1/4)
= 6 -5
= 1

234468/123246
=123246*2/123246
=2
51又2/3÷5/3+71又3/4÷7/4+91又4/5÷9/5
=155/3*3/5+287/4*4/7+459/5*5/9
=31+41+51
=123
1又4/17*(2又2/3-3/4)+17又11/12÷17/21
=21/17*(2+2/3-3/4)+(17+11/12)*21/17
=21/17*(2-1/12)+21+77/68
=21/17*23/12+22+9/68
=22+23*7/68+9/68
=22+170/68
=22+10/4
=22+2.5
=44.5
13又7/13-(4又1/4+3又7/13)-0.75
=13又7/13-3又7/13-(4又1/4+0.75)
=10-5
=5
51又1/4*4/5+61又1/5*5/6+71又1/6*6/7
=205/4*4/5+306/5*5/6+427/6*6/7
=41+51+61
=153 .