Tính nhanh các biểu thức sau :
a) (45 – 5 x 9) x 1 x 2 x 3 x 4 x 5 x 6 x 7
b) (1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10) x (72 – 8 x 8 – 8)
c) (36 – 4 x 9) : (3 x 5 x 7 x 9 x 11)
d) (27 – 3 x 9) : 9 x 1 x 3 x 5 x 7
tính theo mẫu :
Mẫu : ( 5 / 8 x 3 / 4 ) x 4 / 5 = 5 / 8 x ( 3 / 4 x 4 / 5 ) = 5 / 8 x 3 / 5 = 3 / 8
a) ( 4 / 9 x 3 / 7 ) x 7 / 4
b) ( 6 / 5 x 4 / 5 ) x 25 / 16
c) ( 7 / 8 x 16 / 9 ) x 3 / 14
tính theo mẫu :
Mẫu : ( 5 / 8 x 3 / 4 ) x 4 / 5 = 5 / 8 x ( 3 / 4 x 4 / 5 ) = 5 / 8 x 3 / 5 = 3 / 8
a) ( 4 / 9 x 3 / 7 ) x 7 / 4
b) ( 6 / 5 x 4 / 5 ) x 25 / 16
c) ( 7 / 8 x 16 / 9 ) x 3 / 14
Tính bằng cách thuận tiên nhất:
1):(3/4 x 5/97 + 1/9 x 13/47) x (1/5 - 7/25 x 5/7)
2): 8/17 x 4/15 + 8/17 x 22/15 - 8/15 x 9/17
3): 2021/2 x 1/3 + 4042/4 x 1/5 + 6063/3 x 22/15
4); 4/7 x 2/13 + 8/13 :7/4 + 4/7 : 13/2 + 4/7 x 1/13
5): 2022 x 2021 - 1/ 2021 + 2022 x 2020
6): 18 x 123 + 9 x 4567 x 2 + 3 x 5310 x 6 / (2 + 4 + 6 + 8 + ...+20 + 22) + 48
7): A= 2021 x 2021 x 202020 - 2020 x 2020 x 20212021 / 2020 x 20192019
a, X : 1/3 = 4/5
b, X : 3/5 = 7/9
c, X x 3/4 = 7/6
d, 4/8 x X = 9/7
2. Tính bằng hai cách: A) ( 7/9 + 3/5 ) x 2/3. B) ( 9/11 - 3/11 ) x 5/7. C) 7/8 x ( 8/9 - 1/3 ).
2. Tính bằng hai cách: A) ( 7/9 + 3/5 ) x 2/3. B) ( 9/11 - 3/11 ) x 5/7. C) 7/8 x ( 8/9 - 1/3 ).
tính bằng cách thuận tiện nhất :
1/2 x 2/3 x 3/4 x 4/5 x 5/6
1/10 x 2/9 x 3/8 x 4/7 x 5/6 x 6/5 x 7/4 x 3/8 x 9/2
Cho m= 3/5 x (6/7 x 8/9 x 10/11 x ... x 32/33) và N = 5/6 x 7/8 x 9/10 x ... x 31/32
\(\dfrac{3}{7}\) + 4 = ?
\(\dfrac{5}{9}\) x 3 = ?
\(\dfrac{7}{8}\) - \(\dfrac{2}{9}\)= ?
5 - \(\dfrac{3}{4}\)= ?
\(\dfrac{5}{7}\) : 6 = ?
\(\dfrac{5}{6}\) x \(\dfrac{2}{7}\)= ?
3 + \(\dfrac{3}{4}\)= ?
\(\dfrac{3}{5}x\dfrac{4}{8}\) = ?
5 : \(\dfrac{3}{8}\)= ?
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