18/17÷19+1/19×16/17
=18/17 ×1/19+1/19×16/17
=(1/19)×(18/17 + 16/17)
=(1/19)×2
=2/19
(2/3+4/15×5/2)÷20/21
=(2/3+2/3)× 21/20
=(4/3)× 21/20
=7/5
=1又2/5
0.25×1.25×48
=(0.25×4)×(1.25×4)×3
=1×5×3
=15
18/17÷19+1/19×16/17
=18/17 ×1/19+1/19×16/17
=(1/19)×(18/17 + 16/17)
=(1/19)×2
=2/19
(2/3+4/15×5/2)÷20/21
=(2/3+2/3)× 21/20
=(4/3)× 21/20
=7/5
=1又2/5
0.25×1.25×48
=(0.25×4)×(1.25×4)×3
=1×5×3
=15