1) Tinh nhanh:
a) 18*76+24*18-150
b) 147+230+53+70
c) 7*85+27*7-7*12
d) 58*75+58*50-58*25
e)2va3/5-2/5*(5/8-7/12)
f) 1/3-5/4*4/15
Tinh nhanh
a ) 18*76+24*18-150
b ) 147 +230+53+70
c) 7*85+27*7-7*12
d) 58*75+58*50-58*25
e) 2 va3/5-2/5*(5/8-7/12)
f ) 1/3-5/4*4/15
Tim x
50 -2 x ( x +1 )=20
Tinh nhanh
147+230+53+70
7*85+27*7-7*12
58*75+58*50-58*25
Tình nhanh
a) 18x 76 +24x -150
b) 147+230+53+70
c) 7x 85+27 x 7-7 x 12
D) 2va3/5 -2/5x( 5/8-7/12)
Tính nhẩm: 1) 373737 . 73 - 37 . 737373 2)19 . 41414141 - 41 . 19191919 3)123456 . 456789456789 - 456789 . 123456123456 4)250 . 12 . 7 5)24 . 125 . 9 6)125 . 44 . 18 7)8 . 24 . 6 + 12 . 4 . 52 + 2 . 22 . 24 8)18. 58 . 2 - 9 . 27 . 4 + 12 . 69 . 3 9)30 . 85 . 3 + 18 . 72 . 5 - 45 . 37 . 2 - 9 . 20 . 10
1) \(373737.73-37.737373\)
\(=37.10101.73-37.73.10101\)
\(=0\)
2) \(19.41414141-41.19191919\)
\(=19.41.1010101-41.19.1010101\)
\(=0\)
3) \(123456.456789456789-456789.123456123456\)
\(=123456.456789.1000001-456789.123456.1000001\)
\(=0\)
4) \(250.12.7\)
\(=250.4.3.7\)
\(=\left(250.4\right).\left(3.7\right)\)
\(=1000.21\)
\(=21000\)
5) \(24.125.9\)
\(=3.8.125.9\)
\(=\left(3.9\right).\left(8.125\right)\)
\(=27.1000\)
\(=27000\)
6) \(125.44.18\)
\(=125.4.11.2.9\)
\(=\left(125.4.2\right).\left(11.9\right)\)
\(=1000.99\)
\(=99000\)
7) \(8.24.6+12.4.52+2.22.24\)
\(=48.24+48.52+48.22\)
\(=48\left(24+52+22\right)\)
\(=48.98\)
\(=48\left(100-2\right)\)
\(=48.100-48.2\)
\(=4800-96\)
\(=4704\)
8) \(18.58.2-9.27.4+12.69.3\)
\(=36.58-36.27+36.69\)
\(=36\left(58-27+69\right)\)
\(=36.100=3600\)
9) \(30.85.3+18.72.5-45.37.2-9.20.10\)
\(=90.85+90.72-90.37-90.20\)
\(=90\left(85+72-37-20\right)\)
\(=90.100=9000\)
1) 58× 75+ 58× 50 -58 × 25
2) 2và 3/5 - 3/5 × ( 5/8- 7/12)
3) 1/3 - 5/4 × 4/15
1) 58× 75+ 58× 50 -58 × 25
= 58( 75 + 50 - 25 )
= 58 . 100
= 5800
1/ 58 x 75 + 58 x 50 - 58 x 25
= 58 x ( 75 + 50 - 25 )
= 58 x 100
= 5800
2/= \(2\frac{3}{5}-\frac{3}{5}\cdot\frac{11}{84}\)
\(=\frac{13}{5}-\frac{3}{5}\cdot\frac{11}{84}\)
\(=\frac{13}{5}-\frac{11}{140}\)
\(=\frac{364-11}{140}\)
\(=\frac{353}{140}\)
3/ \(\frac{1}{3}-\frac{5}{4}\cdot\frac{4}{15}\)
\(=\frac{1}{3}-\frac{1}{3}\)
\(=0\)
Tính nhanh :
1) 18× 76 + 24 × 18 -150
2) 147+230 +53 + 70
3) 7 × 85 + 27 × 7 - 7 ×12
a,18 . 76 + 24 . 18 - 150 = 18 . ( 76 + 24 ) - 150= 18 . 100 - 150 = 1800 - 150=1650
b, 147 + 230 + 53 + 70 = ( 147 + 53 ) + ( 230 + 70) = 200 + 300=500
c, 7 . 85 + 27 . 7 - 7 . 12=(85 + 27 -12 ) . 7=100 . 7=700
Dấu . là phép nhân
1) 18 . 76 + 24 . 18 -150
= 18( 76 + 24 ) - 150
= 18 . 100 -150
= 1800 - 150
= 1650
2) 147+230 +53 + 70
= ( 147 + 53 ) + ( 230 + 70 )
= 200 + 200
= 400
3) 7 × 85 + 27 × 7 - 7 ×12
= 7( 85 + 27 - 12 )
= 7 . 100
= 700
-12/18 + (-21)/35
-3/21 + 6/42
-18/24 + 15/21
1/6 + 2/5
3/5 + (-7)/4
(-2) + (-5)/8
1/-8 + (-5)/9
4/13 + 12/39
1/21 + 1/28
-3/29 + 16/58
8/40 + (-36)/45
-8/18 + (-15)/27
13/30 + (-1)/5
2/21 + 1/28
5 + (-3)/4
18/24 + 45/-10
câu 1)
\(\dfrac{-12}{18}+\left(\dfrac{-21}{35}\right)=\dfrac{-19}{15}\)
câu 2)
\(-\dfrac{3}{21}+\dfrac{6}{42}=0\)
câu 3)
\(-\dfrac{18}{24}+\dfrac{15}{21}=-\dfrac{1}{28}\)
câu 4)
\(\dfrac{1}{6}+\dfrac{2}{5}=\dfrac{17}{30}\)
câu 5)
\(\dfrac{3}{5}+\left(-\dfrac{7}{4}\right)=-\dfrac{23}{20}\)
câu 6)
\(\left(-2\right)+\left(\dfrac{-5}{8}\right)=\dfrac{-21}{8}\)
câu 7)
\(\dfrac{1}{-8}+\left(-\dfrac{5}{9}\right)=-\dfrac{49}{72}\)
câu 8)
\(\dfrac{4}{13}+\dfrac{12}{39}=\dfrac{8}{13}\)
câu 9)
\(\dfrac{1}{21}+\dfrac{1}{28}=\dfrac{1}{12}\)
câu 10)
\(-\dfrac{3}{29}+\dfrac{16}{58}=\dfrac{5}{29}\)
câu 11)
\(\dfrac{8}{40}+\left(-\dfrac{36}{45}\right)=-\dfrac{3}{5}\)
câu 12)
\(-\dfrac{8}{18}+\left(-\dfrac{15}{27}\right)=-1\)
câu 13)
\(\dfrac{13}{30}+\left(-\dfrac{1}{5}\right)=\dfrac{7}{30}\)
câu 14)
\(\dfrac{2}{21}+\dfrac{1}{28}=\dfrac{11}{84}\)
câu 15)
\(5+\left(-\dfrac{3}{4}\right)=\dfrac{17}{4}\)
câu 16)
\(\dfrac{18}{24}+\dfrac{45}{-10}=-\dfrac{15}{4}\)
1 . Tính nhanh
a/ 15 . ( 27 + 18 + 6 ) + 15 . ( 23 + 12 )
b/ 14 . 35 . 5 + 10 . 25 .7 + 20 . 70
c/ 53 . ( 51 + 4 ) + 53 . ( 49 + 96 ) + 53
d/ 46 . ( 27 + 75 ) + 8 . ( 58 + 25 ) . 2
a) 15 . (27 + 18 + 6 ) + 15 . ( 23 +12 ) = 15. 51 + 15 . 35 = 765 + 525 = 1290
b) 14 . 35 . 5 + 10 . 25 . 7 + 20 . 70 = 2450 + 1750 + 1400 = 2452450
c) 53 . ( 51 + 4 ) + 53 . ( 49 + 96 ) + 53 = 53 . 55 + 53 . 145 + 53 = 2915 . 7685 = 22401775
d) 46 . ( 27 +75 ) +8 . ( 58 + 25 ) + 8 . ( 58 + 25 ) . 2 = 46 . 102 + 8 . 83 + 8 . 83 = 4692 + 664 + 664 = 6020
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