123.456+123.789-1245.23

=123.(456+789)-1245.23

=123.1245-1245.23

=1245.(123-23)

=1245.100

=124500

=123.(456+789)-1245.23

=123.1245-1245.23

=1245.(123-23)

=1245.100

=124500

a)(bạn kia làm rồi)

b)2^9:16^2+81^5:3^18-125^7:625^5

=2^9:(2^4)^2+(3^4)^5:3^18-(5^3)^7:(5^4)^5

=2^9:2^8+3^20:3^18-5^21:5^20

=2+3^2+5

=2+9+5

=16

a)Ta có\(123\times456+123\times789+1245\times23\)

           \(=123\left(456+789\right)+1245.23\)

           \(=123.1245+1245.23\)

            \(=1245\left(123+23\right)\)

             \(=1245.146\)

              \(=181770\)

b)\(2^9:16^2+81^5:3^{18}-125^7:625^5\)

\(=2^9:\left(2^4\right)^2+\left(3^4\right)^5:3^{18}-\left(5^3\right)^7:\left(5^4\right)^5\)

\(=2^9:2^8+3^{20}:3^{18}-5^{21}:5^{20}\)

\(=2+3^2-5\)

\(=2+9-5\)

\(=6\)

\(2^9\div16^2+81^5\div3^{18}-125^7\div625^5\)

\(=2^9\div\left(2^4\right)^{^2}+\left(3^4\right)^{^5}\div3^{18}-\left(5^3\right)^{^7}\div\left(5^4\right)^{^5}\)

\(=2^9\div2^8+3^{20}\div3^{18}-5^{21}\div5^{20}\)

\(=2^1+3^2-5^1\)

\(=2+9-5\)

\(=6\)

A) 11/125+(-17/18+4/9)-(5/7-17/14)

 =11/125+(-17/18+8/18)-(10/14-17/14)

=11/125+(-1/2)-(-1/2)

=11/125

B)(1+2+3+4-3-2-1)-(1/2+1/2+2/3+1/3+3/4+1/4)

 =4-3

=1

à bn lấy trong sách các dạng toán và phương pháp giải hả

a, 12^7 : 6^7 = (12 : 6)^7 = 2^7 = 128.

b,27^5 : 81^3 = (3^3)^5 : (3^4)^3 = 3^15 : 3^12 = 3^15 - 12 = 33 = 27

c,18^3 : 9^3 = (18 : 9)^3 = 2^3 = 8.

d, 125^3 : 2^4 = (5^3)^3 : (52)4 = 5^9 : 5^8 = 5^9 - 8 = 5.

a,vì có cùng số mũ =>12:6=2

b,ta có 125=(5^3)^5,25^3=(5^2)^3=>5^15:5^6=5^9

c,ta có 27^5=(3^3)^5,81^3=(3^4)^3=>3^15:3^12=3^3

d, vì có cùng số mũ =>18:9=2

halo

a)\(\frac{-5}{18}+\frac{32}{45}-\frac{9}{10}\)

\(=\frac{-25}{90}+\frac{64}{90}-\frac{81}{90}\)

\(=-\frac{42}{90}=-\frac{7}{15}\)

b)\(\frac{3}{4}-\left(-\frac{5}{8}\right)+\frac{9}{4}-\frac{3}{16}\)

\(=\frac{3}{4}+\frac{5}{8}+\frac{9}{4}-\frac{3}{16}\)

\(=\frac{12}{16}+\frac{10}{16}+\frac{36}{16}-\frac{3}{16}\)

\(=\frac{58}{16}=\frac{29}{8}\)

c) \(\frac{11}{125}-\frac{17}{18}-\frac{5}{7}+\frac{4}{9}+\frac{17}{14}=\frac{11}{125}\)

d) \(\frac{-2}{5}-\frac{3}{10}-\left(-\frac{1}{2}\right)\)

\(=-\frac{2}{5}-\frac{3}{10}+\frac{1}{2}\)

\(=-\frac{4}{10}-\frac{3}{10}+\frac{5}{10}\)

\(=-\frac{2}{10}=-\frac{1}{5}\)

1, \(81\cdot27^3\cdot243^5=3^4\cdot3^9\cdot3^{25}=3^{38}\)

2,\(25^4\cdot125^3\cdot625^7=5^8\cdot5^9\cdot5^{28}=5^{45}\)

3,

\(16^3\cdot8^9\cdot64^5\cdot1024=2^{12}\cdot2^{27}\cdot2^{30}\cdot2^{10}=2^{79}\)

( 625² + 3 ).( 5⁸ - 3 )  - 5¹⁶ + 10

= [ ( 5⁴ )² + 3 ).(  5⁸ - 3 )  - 5¹⁶ + 10

= ( 5⁸ + 3 ).( 5⁸ - 3 ) - 5¹⁶ + 10

=  5¹⁶ -9 - 5¹⁶ + 10

= 1

a) 1 - 3 + 5 - 7 + 9 - 11

= (1 - 3) + (5 - 7) + (9 - 11)

= (-2) + (-2) + (-2)

= -6

b) -14 - 16 - 18 - ... - 92

= - (14 + 16 + 18 + .... + 92)

Áp dụng công thức tính dãy số ta có :

14 + 16 + 18 + .... + 92 = 2120

= -2120

c) 15 + 18 + 21 + .... + 63 + 66 + 70

= (15 + 18 + 21 + ..... + 66) + 70

Áp dụng công thức tính dãy số ta có :

15 + 18 + ..... + 66 = 729

= 729 + 70

= 8799

d) 2 - 3 + 4 - 5 + 6 - 7 + 8 - 9 + 10

= (2 - 3) + (4 - 5) + (6 - 7) + (8 - 9) + 10

= (-1) + (-1) + (-1) + (-1) + 10

= 6

a)1-3+5-7+9-11=-6

nhớ k cho mk nha,mk đầu tiên đấy nha bn