四年级数学下册简便计算题加答案 横式计算 速度求
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1. 67 ×21 +18 ×21 + 85 ×79
2. 375 ×480 + 6250 ×48
3. 321 ×81 + 321 ×19
4. 222222 ×999999
5. 333333 ×333333
6. 654321 ×909090 +654321 ×90909
7. 34 ×3535 -35 ×3434
8. 345345 ÷15015
9. 75 ×45 + 17 ×25
10. (48 ×75 ×81)÷(24 ×25 ×27)
【答案详解】
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
希望能帮到你,望采纳,谢谢!
2. 375 ×480 + 6250 ×48
3. 321 ×81 + 321 ×19
4. 222222 ×999999
5. 333333 ×333333
6. 654321 ×909090 +654321 ×90909
7. 34 ×3535 -35 ×3434
8. 345345 ÷15015
9. 75 ×45 + 17 ×25
10. (48 ×75 ×81)÷(24 ×25 ×27)
【答案详解】
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
希望能帮到你,望采纳,谢谢!
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