Tính hợp lí : \(4.24.5^2-\left(3^3.18+3^3.12\right)\)
tính hợp lí
4.24.5^2-(3^3.18+3^3.12)
tính nhanh nha các bạn
4 . 24 . 5 ^ 2 - ( 3 ^ 3 . 18 + 3 ^ 3 . 12 )
= 4 . 24 . 25 - ( 9 . 18 + 9 . 12 )
= ( 4 . 25 ) . 24 - 9 . ( 18 + 12 )
= 100 . 24 - 9 . 30
= 2400 - 270
= 2130
\(4.24.5^2-\left(3^3.18+3^3.12\right)\)
=\(24.100-3^3\left(18+12\right)\)
=\(24000-270=23730\)
thực hiện các phép tính bằng cách hợp lí nhất
a)\(\frac{5}{3}+\left(\frac{-2}{7}\right)-\left(-1,2\right)\)
b)\(\frac{-4}{9}+\left(\frac{-5}{6}\right)-\frac{17}{4}\)
Thực hiện phép tính :
a) \(5.4^2-18:3^2\)
b) \(3^3.18-3^3.12\)
c) \(39.213+87.39\)
d) \(80-\left[130-\left(12-4\right)^2\right]\)
a) 5 . 42 – 18 : 32 = 5 . 16 - 18 : 9 = 80 - 2 = 78;
b) 33 . 18 – 33 . 12 = 27 . 18 - 27 . 12 = 486 - 324 = 162;
Lưu ý. Có thể áp dụng tính chất phân phối của phép nhân đối với phép cộng:
33 . 18 – 33 . 12 = 33 (18 - 12) = 27 . 6 = 162;
c) 39 . 213 + 87 . 39 = 39 . (213 + 87) = 39 . 300 = 11700;
d) 80 – [130 – (12 – 4)2] = 80 - (130 - 64) = 80 - 66 = 14.
Tính hợp lí:
B= \(\frac{1}{3}-\frac{3}{4}-\left(-\frac{3}{5}\right)+\frac{1}{20}-\frac{2}{9}-\frac{1}{36}+\frac{1}{15}+\frac{3}{20}\)
3 mũ 3.18-3 mũ 3.12
33 x 18 - 33 x 12
= 27 x 18 - 27 x 12
= 486 - 27 x 12
= 486 - 324
= 162
nha bn
Tính bằng cách hợp lí nhất
a) A = \(\frac{\left(1+17\right)\left(1+\frac{17}{2}\right)\left(1+\frac{17}{3}\right)...\left(1+\frac{17}{19}\right)}{\left(1+19\right)\left(1+\frac{19}{2}\right)\left(1+\frac{19}{3}\right)..\left(1+\frac{19}{17}\right)}\)
b) B = \(\left(\frac{1}{2}-1\right)\left(\frac{1}{3}-1\right)...\left(\frac{1}{99}-1\right)\left(\frac{1}{100}-1\right)\)
tính hợp lí
3.(-4)^2+2.(-5)-20
3.(-4)2 + 2.(-5) - 20
= 3.16 + 2.(-5) - 20
= 3.8.2 + 2.(-5) - 2.10
= 24.2 + 2.(-5) - 2.10
= (24 - 5 - 10) . 2
= 9.2
= 18
3.(-4)2 + 2.(-5) - 20
= 3.16 + 2.(-5) - 2.10
= 3.8.2 + 2.(-5) - 2.10
= 24.2 + 2.(-5) - 2.10
= ( 24 - 5 - 10 ) .2
= 9.2
= 18
Kết quả là = 18
thực hiện phép tính hợp lí
a, \(5\frac{3}{7}+\frac{7}{29}-0,7-\frac{3}{17}+\frac{22}{19}-2,3\)
b, \(0,375.\left(-1,5\right).\left(-4\right)^2\)
c, \(1\frac{1}{14}-\frac{7}{2}+2\frac{1}{14}:\left(\frac{-7}{2}\right)\)
d, \(\sqrt{0.36}-\sqrt{0,81}+\sqrt{0,49}\)
a) \(5\frac{3}{7}+\frac{7}{29}-0,7-\frac{3}{17}+\frac{22}{19}-2,3\)
\(=\frac{38}{7}+\frac{7}{29}-\frac{7}{10}-\frac{3}{17}+\frac{22}{19}-\frac{23}{10}\)
\(=\left(-\frac{7}{10}-\frac{23}{10}\right)+\frac{38}{7}+\frac{7}{29}-\frac{3}{17}+\frac{22}{19}\)
\(=\left(-3\right)+\frac{38}{7}+\frac{7}{29}-\frac{3}{17}+\frac{22}{19}\)
\(=\frac{17}{7}+\frac{7}{29}-\frac{3}{17}+\frac{22}{19}\)
\(=\frac{8605}{3451}+\frac{22}{19}\)
\(\approx4.\)
d) \(\sqrt{0,36}-\sqrt{0,81}+\sqrt{0,49}\)
\(=0,6-0,9+0,7\)
\(=\left(-0,3\right)+0,7\)
\(=0,4.\)
Chúc bạn học tốt!
Tính hợp lí:
A = \(\left(\frac{-4}{5}+\frac{4}{3}\right)+\left(\frac{-5}{4}+\frac{14}{5}\right)-\frac{7}{3}\)
B= \(\frac{8}{3}.\frac{2}{5}.\frac{3}{8}.10.\frac{19}{92}\)
C= \(\frac{-5}{7}.\frac{2}{11}+\frac{-5}{7}.\frac{9}{14}+1\frac{5}{7}\)
A= (-4/5+4/3)+(-5/4+14/5)-7/3
= 8/15+31/20-7/3
= 25/12-7/3
= -1/4
B= 8/3.2/5.3/8.10.19/92
= 16/15.3/8.10.19/92
= 2/5.10.19/92
= 4.19/92
= 19/23
C= \(\frac{-5}{7}\).\(\frac{2}{11}\)+\(\frac{-5}{7}\).\(\frac{9}{14}\)+1\(\frac{5}{7}\)
=\(\frac{-5}{7}\).\(\frac{2}{11}\)+\(\frac{-5}{7}\).\(\frac{9}{14}\)+\(\frac{12}{7}\)
= \(\frac{-10}{77}\)+\(\frac{-5}{7}\).\(\frac{9}{14}\)+\(\frac{12}{7}\)
= \(\frac{-10}{77}\)+\(\frac{-45}{98}\)+\(\frac{12}{7}\)
= \(\frac{-635}{1078}\)+\(\frac{12}{7}\)
= \(\frac{1213}{1078}\)