问题 填空题
先估一估括号内可填几,再用计算器检验,得出正确的答案.
算式积的范围估计的数检查的结果
29×______1000-2000____________
167×______6000-7000____________
405×______8000-9000____________
答案

29×42≈30×40=1200,

29×42=1218,

167×42≈160×40=6400,

167×42=6847,

405×22≈400×20=8000;

405×22=8910;

故答案为:42,40,1218;41,40,6847,22,20,8910.

选择题
问答题 论述题