①（0.4×0.8）×（2.5×32.5）②0.52×249+759×0.52．

Question

①（0.4×0.8）×（2.5×32.5）
②0.52×2 (4)/(9) +7 (5)/(9) ×0.52．

Answer 1

①（0.u×0.8）×（2.5×22.5）
=（0.u×2.5）×（0.8×22.5）
=2×20
=20；
②0.52×2 (u)/(9) +7 (5)/(9) ×0.52
=0.52×（2 (u)/(9) +7 (5)/(9) ）
=0.52×20
=5.2．