Question

脱式计算，能用简便方法计算的要用简便方法计算．62×7.1+2.9 4.2×0.25 5.2×4.3+0.8×4.3．

脱式计算，能用简便方法计算的要用简便方法计算．62×7.1+2.9 4.2×0.25 5.2×4.3+0.8×4.3．

Answer 1

（1）62×7.1+2.9，
=440.2+2.9，
=443.1；

（2）4.2×0.25，
=（4+0.2）×0.25，
=4×0.25+0.2×0.25，
=1+0.05，
=1.05；

（3）5.2×4.3+0.8×4.3，
=（5.2+0.8）×4.3，
=6×4.3，
=25.8．