tinh nhanh: 152; 252;452; 652.Tu do suy ra ket luan gi?
Tinh nhanh :
C = 1/2 + 1/14 + 1/35 + 1/65 + 1/104 + 1/152
\(C=\frac{1}{1.2}+\frac{1}{2.7}+\frac{1}{5.7}+\frac{1}{5.13}+\frac{1}{8.13}+\frac{1}{8.19}\)
\(\frac{3}{2}C=\frac{3}{2}\)(\(\frac{1}{1.2}+\frac{1}{2.7}+\frac{1}{5.7}+\frac{1}{5.13}+\frac{1}{8.13}+\frac{1}{8.19}\))
\(\frac{3}{2}C=\frac{3}{1.4}+\frac{3}{4.7}+\frac{3}{7.10}+\frac{3}{10.13}+\frac{3}{13.16}+\frac{3}{16.19}\)
\(\frac{3}{2}C=1-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+\frac{1}{7}-\frac{1}{10}+\frac{1}{10}-\frac{1}{13}+\frac{1}{13}-\frac{1}{16}+\frac{1}{16}-\frac{1}{19}\)
\(\frac{3}{2}C=1-\frac{1}{19}=\frac{18}{19}\)
\(C=\frac{18}{19}:\frac{3}{2}=\frac{12}{19}\)
tinh nhanh
4x950x9+18x726x2+3x24x12
___________________________
1+3+5+7+....+27+29+31-152
Tinh nhanh :
a/1990 . 1990 - 1992.1998
b/( 1374 . 57 + 687 . 86 ) : ( 26 . 13 + 74 . 14 )
c/( 124 . 237 + 152 ) : ( 870 + 235 . 122 )
1/tinh nhanh:
M=1/4+152/11+68/4>1/11
N=9/25.53/3-9/5.5.22/3
P=2/5.4.3/5.7,3/2
Q=(31/10-5/2)-3=2
Tinh nhanh
a) 19.64+76.34=
b) 35.12+65.13
c)136.68+16.272
b) ( 2+4+6+...+100).(36.333- 108.111)
e) 19991999.1998-19981998.1999=
f) 2014.2014-2016:2012
h) (124.237+152) : ( 870+ 235.122)
a) 19.64+76.34=19.64+19.4.34=19.(64+136)=19.200=3800
b) 35.12+65.13=35.12+65.12+65=12.(35+65)+65=12.100+65=1265
c) 136.68+16.272=136.68+32.136=136.(68+32)=136.100=13600
d) ( 2+4+6+...+100).(36.333 - 108.111)=(....).(108.111 - 108.111)=(....).0=0
a) 19. 64+76.34
=19 . 2. 32+ 38.2 . 34
=38.32+38.68
=38. (32+68)
=38.100
=3 800
b)35.12+65.13
=35.12+65.(12+1)
=35.12+65.12+65
=12.(35+65)+65
=12.100+65
=1 200 +65
=1265
19x64+19x34
=19x(64+34)
=19x98
=19x(100-2)
=19x100-19x2
=1900-38
=1862
tính nhanh :152 . 75 + ( 152 + 4 ) .25 =
mik dang cần gấp
152 . 75 + ( 152 + 4 ) .25 = ( 152 . 3 ) . 25 + ( 152 + 4 ) .25
= 456 . 25 + 156 . 25
= 25 . ( 456 + 156 )
= 25 . 612
= 15300
\(152\cdot75+\left(152+4\right)\cdot25\)
\(=152\cdot75+152\cdot25+25\cdot4\)
\(=152\cdot\left(75+25\right)+100\)
\(=152\cdot100+100\cdot1\)
\(=100\cdot\left(152+1\right)\)
\(=100\cdot153\)
\(=15300\)
Tính nhanh
1 )152 x 9 + 152
2) 24 x 999 + 24
1) \(152\times9+152\times1=152\times\left(9+1\right)=152\times10=1520\)
2) \(24\times999+24\times1=24\times\left(999+1\right)=24\times1000=24000\)
1/ 152 x 9 + 152 x 1 = 152 x ( 9 + 1 ) = 152 x 10 = 1520
2/ 24 x 999 + 24 x 1 = 24 x ( 999 + 1 ) = 24 x 1000 = 24000
Giúp mik lần nữa, lần này mik sẽ tik cho 5 người nha:
Tính nhanh \(692+152-92\)
\(692+152-92=\left(692-92\right)+152=600+152=752\)
\(692+152-92=692-92-152=600-152=448\)
Giúp mik điền đúng (Đ) hay sai (S) nha
692 + 152 - 92
= (692 - 92) + 152
= 600 + 152
752
Tính nhanh 692+152−92
692+152−92=(692−92)+152=600+152=752 ( Đúng )
\(692+152-92=692-92-152=600-152=752\)( Sai )
Tính nhanh: 25 2 – 15 2
25 2 – 15 2 = (25 + 15)(25 – 15) = 40.10 = 400
tính nhanh
a)A=54.34-(152-1)(152+1)
b)C=502-492+482-472+...+22-12
(14,78-a)/(2,87+a)=4/1
14,78+2,87=17,65
Tổng số phần bằng nhau là 4+1=5
Mỗi phần có giá trị bằng 17,65/5=3,53
=>2,87+a=3,53
=>a=0,66.
a) A= 54 . 34- (152-1).(152+1)
=(5.3)4-154-1
=154-154-1
=-1
a) A= 54.34 -(152-1).(152+1)
=(5.3)4 - (154-1)
= 154 - 154 +1
= 1