五升六预习3.3《分数四则混合运算》(6个技巧)专项训练(含答案)新人教版六年级数学上册

3.3《分数四则混合运算》（6个技巧）专项训练 技巧一：遇除法统一变乘法 类型一 转化为连乘凑约分 1. 2. 3. 4. 5. 类型二 转化为含相同公因数 1. 2. 3. 4. 5. 6. 7. 类型三 加减和差除以分数变乘法分配律 1. 2. 3. 4. 5. 6. 类型四 无法简便直接按顺序 1. 2. 技巧二：有括号先算括号 1. 2. 3. 4. 5. 6. 7. 技巧三：无括号 先乘除后加减 1. 2. 3. 4. 5. 6. 7. 8. 技巧四：含小数、带分数化分数 1. 2. 3. 4. 技巧五：乘法分配律易错对比 1. 2. 3. 4. 5. 6. 7. 8. 9. 技巧六：拆分凑整简便运算 1. 2. 3. 4. 5. 6.3.3《分数四则混合运算》（6 个技巧）专项训练 技巧一：遇除法统一变乘法 类型一 转化为连乘凑约分 1.8 ÷ 4 × 3 9 10 = 8 × 1 × 3 = 1 9 4 10 15 2.5 ÷ 2 ÷ 5 6 3 8 = 5 × 3 × 8 = 2 6 2 5 3.3 × 5 ÷ 3 × 5 4 6 4 6 = 3 × 5 × 4 × 5 = 1 × 25 = 25 4 6 3 6 36 36 4.1 ÷ 2 × 7 × 12 3 5 12 7 = 1 × 5 × 7 × 12 = 5 × 1 = 5 3 2 12 7 6 6 5. 5 × 4 ÷ 5 × 4 12 9 12 9 = 5 × 12 × 4 × 4 = 1 × 16 = 16 12 5 9 9 81 81 类型二 转化为含相同公因数 1. 5 ÷ 4 + 6 ÷ 4 11 9 11 9 = 5 × 9 + 6 × 9 = 9 × 5 + 6 = 9 × 1 = 9 11 4 11 4 4 11 11 4 4 2.9 ÷ 3 2 × 9 8 2 3 8 = 9 × 2 2 × 9 = 0 8 3 3 8 3.4 ÷ 4 + 3 × 1 7 7 4 = 4 × 1 + 3 × 1 = 1 × 4 + 3 = 1 7 4 7 4 4 7 7 4 4. 5 ÷ 13 + 1 × 7 12 13 12 = 5 × 1 + 1 × 7 = 1 × 5 + 7 = 1 12 13 13 12 13 12 12 13 5.1 × 7 + 1 ÷ 12 5 12 5 第 1 页共 6 页 = 1 × 7 + 1 × 1 = 1 × 8 = 2 5 12 5 12 5 12 15 6. 7 ÷ 17 + 1 × 12 + 1 19 17 19 17 = 1 × 7 + 12+ 1 = 1 × 2 = 2 17 19 19 17 17 7.252÷ 6 + 252÷ 6 5 = 252 × 1 + 252 × 5 = 252 × 1+ 5 = 252 6 6 6 6 类型三 加减和差除以分数变乘法分配律 1. 2 + 3 5 ÷ 1 3 4 6 24 = 2 + 3 5 × 24 = 16 + 18 20 = 14 3 4 6 2. 2 + 7 1 ÷ 1 5 10 2 40 = 2 × 40 + 7 × 40 1 × 40 = 16 + 28 20 = 24 5 10 2 3. 5 + 1 + 3 ÷ 1 6 8 4 48 = 5 × 48 + 1 × 48 + 3 × 48 = 40 + 6 + 36 = 82 6 8 4 4. 12 3 ÷ 9 4 20 = 45 × 20 = 25 4 9 5. 5 1 ÷ 1 9 6 18 = 5 × 18 1 × 18 = 10 3 = 7 9 6 6. 3 + 2 1 ÷ 1 8 3 12 72 = 3 × 72 + 2 × 72 1 × 72 = 27 + 48 6 = 69 8 3 12 类型四 无法简便直接按顺序 1.36÷ 1 2 1 9 3 = 36÷ 4 = 36 × 9 = 81 9 4 2.8÷ 4 4 ÷ 8 7 7 第 2 页共 6 页 = 14 1 = 13 13 14 14 技巧二：有括号先算括号 1. 7 ÷ 3+ 1 12 4 6 = 7 ÷ 11 = 7 12 12 11 2.36÷ 1 + 3 × 8 6 8 13 = 36÷ 13 × 8 = 36÷ 1 = 108 24 13 3 3.1÷ 2 ÷ 3 5 7 = 1÷ 2 × 7 = 1÷ 14 = 15 5 3 15 14 4. 7 + 11 1 ÷ 1 15 15 3 4 = 7 + 6 × 4 = 7 + 24 = 31 15 15 15 15 15 5.1 ÷ 3 2 × 20 6 4 5 = 1 ÷ 7 × 20 = 1 ÷ 7 = 1 6 20 6 42 6.6÷ 3 + 1 × 1 7 4 19 = 6÷ 19 × 1 = 6÷ 1 = 168 28 19 28 7. 5 ÷ 9 5 11 11 7 16 16 = 5 ÷ 9 1 = 5 ÷ 2 = 35 11 7 11 7 22 技巧三：无括号先乘除后加减 1.3 + 2.4 × 5 4 12 = 3 + 1 = 7 4 4 2.4 5 × 6 3 3 25 5 = 4 2 3 = 4 1 = 3 5 5 3.3 7 ÷ 14 1 15 25 2 = 3 5 1 = 3 4 = 5 6 2 3 3 第 3 页共 6 页 4.2 5 ÷ 6 8 7 = 2 35 = 1 13 48 48 5.8 + 35 ÷ 7 48 12 = 8 + 5 = 9 1 4 4 6.36÷ 6 36 11 = 66 36 = 30 7.25 7 5 5 12 8 24 = 25 14 + 15 + 5 = 25 34 = 23 7 24 24 24 24 12 8.16.5 18.6 × 1 6 = 16.5 3.1 = 13.4 技巧四：含小数、带分数化分数 1.13 ÷ 2.6 × 3 15 4 = 13 ÷ 13 × 3 = 1 × 3 = 1 15 5 4 3 4 4 2.(4 0.8) ÷ 6 11 = 3.2 × 11 = 16 × 11 = 88 6 5 6 15 3. 7 ÷ 0.4 × 3 25 ... ...