Question

下列各题，怎么算简便就怎么算∴4.7×4.7+4.7×6.3-4.712.5×3.2×0.25 4.65×32+2.5×46.5+0.465×4.

下列各题，怎么算简便就怎么算∴4.7×4.7+4.7×6.3-4.712.5×3.2×0.25 4.65×32+2.5×46.5+0.465×4307.25×67.875+725×0.7875+7250×0.05337550.1+0.3+0.5+0.7+0.9+0.11+0.13+0.15+0.17+0.19+…+0.99．

Answer 1

（1）4.7×4.7+4.7×6.3-4.7
=4.7×（4.7+6.3-1）
=4.7×10
=47；

（2）12.5×3.2×0.25    
=（12.5×0.8）×（4×0.25）
=10×1
=10；

（3）4.65×32+2.5×46.5+0.465×430
=4.65×32+25×4.65+4.65×43
=4.65×（32+25+43）
=4.65×100
=465；

（4）7.25×67.875+725×0.7875+7250×0.0533755
=7.25×（67.875+78.75+53.3755）
=7.25×200.0005
=1450.00362；

（5）0.1+0.3+0.5+0.7+0.9+0.11+0.13+0.15+0.17+0.19+…+0.99
=（0.1+0.99）×50÷2
=1.09×50÷2
=27.25．