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4^15 x 5^30 = 2^30 x 5^30 = 10^30

\(\frac{11}{1.12}+\frac{11}{12.23}+\frac{11}{23.34}+.......+\frac{11}{78.89}+\frac{11}{98.100}\)

\(=1-\frac{1}{12}+\frac{1}{12}-\frac{1}{23}+....+\frac{1}{89}-\frac{1}{100}\)

\(=1-\frac{1}{100}\)

\(=\frac{99}{100}\)

\(\dfrac{11}{34}+\dfrac{5}{23}+\dfrac{23}{34}+\dfrac{18}{23}\)
\(=\left(\dfrac{11}{34}+\dfrac{23}{34}\right)+\left(\dfrac{5}{23}+\dfrac{18}{23}\right)\)
\(=1+1\)
\(=2\)
#DatNe

=2

\(\dfrac{11}{34}+\dfrac{5}{23}+\dfrac{23}{34}+\dfrac{18}{23} =\left(\dfrac{11}{34}+\dfrac{23}{34}\right)+\left(\dfrac{5}{23}+\dfrac{18}{23}\right)=\dfrac{34}{34}+\dfrac{23}{23}=1+1=2\)

* là gì z bn

Dấu nhân bạn ạ!

lớp 1 mà cậu

4.24.5²-(3³.18+3³.12)

=4.24.25-[27.(18+12)]

=(4.25).24-[27.30]

=100.24-810

=2400-810

=1590

4.24.5^2-(3^3.18+3^3.12)

31.15.7^2.4-31.49.40

1+2+3+4+5+6+7+8+9+10

1+3+5+7+9+11+13+15+19

2+6+10+14+22+23+26+34

5+8+11+14+17+20+23+26+29

1+6+11+16+21+26+31+36+41+47+51

10+13+16+19+22+25+28+31+34+37+40

5+7+9+11+13+15+17+3+8+13+18+23+28

4+7+10+13+16+19+5+9+13+17+21+25 = 1590

#HT#

=23 bạn nhé

k mình nhé

= 23 nha bạn 

k cho mik nha

Chọn C