Question

四年级下册运算定律口算简便计算及答案

四年级下册运算定律口算简便计算及答案运算需要

Answer 1

1. 67 ×21 ＋18 ×21 + 85 ×79
=21×(67+18)+85×79
=21×85+85×79
=85×(21+79)
=8500
2. 375 ×480 + 6250 ×48
=480×(375＋625)
=480000
3. 321 ×81 + 321 ×19
=321×(81+19)
=32100
4. 222222 ×999999
=222222×(1000000－1)
=222222000000－222222
=222221777778
5. 333333 ×333333
=111111×999999
=111111×(1000000－1)
=111111000000－111111
=111110888889
6. 654321 ×909090 +654321×90909
=654321×999999
=654321×(100000－1)
=654321000000－654321
=654320345679
7. 34 ×3535 －35 ×3434
=34×35×101－35×34×101
=0
8. 345345 ÷15015
=345×1001÷(15×1001)
=345÷15×1001÷1001
=23
9. 75 ×45 + 17 ×25
=25×3×45+17×25
=25×(135+17)
=25×152
=25×4×38
=3800
10. （48 ×75 ×81）÷（24 ×25 ×27）
=48÷24×75÷25×81÷27
=2×3×3
=18