2÷3÷7+4÷6÷14+14÷21÷494÷7÷9+8÷14÷18+28÷49÷63=_.
问题描述:
=______. 2÷3÷7+4÷6÷14+14÷21÷49 4÷7÷9+8÷14÷18+28÷49÷63
答
原式=
,2×
×1 3
+4×1 7
×1 6
+14×1 14
×1 21
1 49 4×
×1 7
+8×1 9
×1 14
+28×1 18
×1 49
1 63
=
,
(1+2 21
+1 2
) 1 7
( 1+4 63
+1 2
)1 7
=
.3 2