解:10又9/20+5又1/4+2又1/2等于( 91/5 ),【即等于18.2】
∵已知需求出10又9/20+5又1/4+2又1/2等于多少
∴10又9/20 + 5又1/4 + 2又1/2
= (10×20+9)/20 + (5×4+1)/4 + (2×2+1)/2
= 209/20 + 21/4 + 5/2
= 209/20 + (21×5)/(4×5)+(5×10)/(2×10)
= 209/20 + 105/20 + 50/20
= 314/20 + 50/20
= 364/20
= 91/5
= 18.2
答:10又9/20+5又1/4+2又1/2等于91/5,【即等于18.2】