心算.
2.3+2.2= 5.62﹣2.02= 0.25+1.8=
9.5﹣1.3= 1.3﹣0.8= 3.5﹣0.5=
1.95÷3.05= 2.3+1.6= 5.31﹣2.01=
口算:
369500-256900=
652000-325600=
869500-556900=
854000-625600=
4512000-4500000=
1526000+1574000=
口算:
256800+256600=
256000+365500=
658900+654200=
125600-115600=
2560000-1260000=
15260000-15160000=
口算:
20000+30000=
25000+25000=
35000+25000=
45000-15000=
200000-150000=
120000-20000=
估算:
24560+11260=
21410+21210=
15610+21000=
90410+21060=
95230+21245=
91210+21260=
估算:
705500-50800≈
5035433-205000≈
305500-108900≈
805433+205000≈
855500-579900≈
533533-205130≈