4.7×3.4+0.47×53+4.7×1.3
= 4.7×3.4+4.7x0.1×53+4.7×1.3
=4.7x(3.4+5.3+1.3 )
=4.7x10
=47
0.25×0.9÷0,·25÷0.9
= (0.25×0.9)÷(0,·25x0.9)
=1
0,25×0,9÷0,25×0,9
= 0.25×0.9÷(1/4)x0.9
= 0.25×0.9x4x0.9
=0.81
5,3×2.5+25×0,48-0,25
=5.3x2.5+2.5x10x0.48-2.5x0.1
=2.5x(5.3+4.8-0.1)
=2.5x10
=25