Tính giá trị của biểu thức a) 25 489 + 9 024 – 10 365 g) 312,56 + 105,78 – 68,124 b) 2 348 × 48 – 6 245
a) 25 489 + 9 024 – 10 365 = 34 513 – 10 365 = 24 148 | g) 312,56 + 105,78 – 68,124 = 418,34 – 68,124 = 350,216 |
b) 2 348 × 48 – 6 245 = 112 704 – 6 245 = 106 459 | h) 30,56 × 2,5 + 4,98 = 76,4 + 4,98 = 81,38 |
c) 60 250 : 5 + 15 423 – 5 797 = 12 050 + 15 423 – 5 797 = 27 473 – 5 797 = 21 676 | i) 360,57 : 3 – 59,209 = 120,19 – 59,209 = 60,981 |
d) \[\frac{3}{5} + \frac{1}{2} + \frac{7}{{10}}\] \[ = \frac{6}{{10}} + \frac{5}{{10}} + \frac{7}{{10}}\] \[ = \frac{{18}}{{10}} = \frac{9}{5}\] | j) \[\frac{7}{4} - \frac{2}{5} - \frac{3}{{20}}\] \[ = \frac{{35}}{{20}} - \frac{8}{{20}} - \frac{3}{{20}}\] \[ = \frac{{24}}{{20}} = \frac{6}{5}\] |
e) \[\frac{3}{5} \times \frac{1}{2} + \frac{5}{2} \times \frac{3}{5} + \frac{4}{2} \times \frac{3}{5}\] \[ = \frac{3}{5} \times \left( {\frac{1}{2} + \frac{5}{2} + 2} \right)\] \[ = \frac{3}{5} \times \left( {\frac{1}{2} + \frac{5}{2} + \frac{4}{2}} \right)\] \[ = \frac{3}{5} \times \frac{{10}}{2}\] = 3 | k) \[\frac{3}{2}:\frac{5}{2} + \frac{3}{2}:\frac{{10}}{7}\] \[ = \frac{3}{2} \times \frac{2}{5} + \frac{3}{2} \times \frac{7}{{10}}\] \[ = \frac{3}{2} \times \left( {\frac{2}{5} + \frac{7}{{10}}} \right)\] \[ = \frac{3}{2} \times \left( {\frac{4}{{10}} + \frac{7}{{10}}} \right)\] \[ = \frac{3}{2} \times \frac{{11}}{{10}}\] \[ = \frac{{33}}{{20}}\] |
f) 4 × 50 × 125 × 2 × 8 = (125 × 8) × (50 × 2) × 4 = 1 000 × 100 × 4 = 400 000 | l) 3,5 : 0,5 + 12,46 : 0,125 + 4,3 : 0,2 = 3,5 × 2 + 12,46 × 8 + 4,3 × 5 = 7 + 99,68 + 21,5 = 106,68 + 21,5 = 128,18 |