Примеры по математике ГИА
05 Ноя 2013, Автор: Сергей ПанчешныйПродолжаем решать примеры по математике ГИА задание № 1.
1. Вычислить: 0,5·0,05·0,005 = 5/10·5/100·5/1000 = 125/1000000 = 0,000125
2. 0,875·2 2/7 = (875/1000)·(16/7) = 875·16/1000·7 = 25·7·5·4·2·2/25·5·4·2·7 = 2
3. 4,2·1,8/6,3 = 42·18/630 = 2·3·7·3·3·2/2·3·3·5·7 = 3·2/5 = 6/5 = 1,2
4. -15/32 + 0,7 = – 15/32 + 7/10 = – 15·5/32·5 + 7·16/10·16 = (-75+112)/160 = 37/160
5. 8/9 +(2/3)·1,7 = 8/9 + (2/3)·(17/10) = 8/9 + 34/30 = 80/90 + 102/90 = 182/90 = 2 1/45
6. 1,2·2,8/4,8 = 12·28/480 = 28/40 = 7/10 = 0,7
7. 20,4·3,5/10,5 = 204·35/1050 = 2·2·3·17·5·7/2·3·5·5·7 = 2·17/5 = 34/5 = 68/10 = 6,8
8. (4 2/3 – 3/7) ·2,625: (9 8/9) = (14/3 – 3/7) · ( 2 5/8):(89/9) = [(14·7-3·3)/21]·(21/8)·(9/89) = 89·21·9/21·8·89 = 9/8 = 1,125
9. (3,2 + 8,4):( 1 3/5)·(1/25) = 11.6:(8/5)·(1/25) = (58/5)·(5/8)·(1/25) = 58·5·1/5·8·25 = 58/200 = 29/100 = 0,29
10. (5 2/3 – 4 1/6) ·( 3 1/3) = ( 5 4/6 – 4 1/6) ·(10/3) = (1 3/6)·(10/3) = (1 1/2)·(10/3) = 3/2 · 10/3 = 30/6 = 5
11. -7 -10: (22,5) – 5 ·1/6 = -7 + 4 – 5/6 = -3 -5/6 = -3 5/6
12. (2,5 – 3 1/2):0,5 = (2,5-3,5):0,5 = (-1):0,5 = (-10):5 = -2
13. (3,6 – 3 1/3)·0,3 = (3 3/5 – 3 1/3)·0,3 =( 3 9/15 – 3 5/15)·0,3 = 4/15 ·3/10 = 4·3/15·10 = 4/50 = 8/100 = 0,08
14. (3 1/5 – 1,1):1/5 = (3,2-1,1):0,2 = 2,1:0,2 = 21:2 = 10,5
15. (5,5 – 2 5/6):4 – 1 = ( 5 1/2 – 2 5/6):4 – 1 = (5 3/6 – 2 5/6):4 – 1 = (4 9/6 – 2 5/6):4 – 1 = (2 4/6):4 – 1 = (16/6):4 – 1 = 16/6·4 – 1= 2/3 – 1 = - 1/3
16. 0,9·3000·0,0003 = 9·3·3·1000/10·10000 = 0,81
17. 20·0,04·8000 = 2·10·4·8·1000/100 = 6400
18. (7/8):14 + 15·[(1/2)²]² = 7/8·14 + 15/16 = 1/16 + 15/16 = 1
19/ 17:(17/30) -(1/3)²·18 = 30 – (1/9)·18 = 30-2 = 28
20. 6·(13/2 – 19/3) = 6·(13·3/2·3 – 19·2/2·3) = 6·(39/6 – 38/6) = 6·1/6 = 1
Продолжение примеров по математике ГИА следует…