0.1+0.2+0.3+...+0.8+0.9+0.12+0.14+0.16+...+0.88 = How much is it,

0.1+0.2+0.3+...+0.8+0.9+0.12+0.14+0.16+...+0.88 = How much is it,

0.1+0.2+0.3+...+0.8+0.9+0.12+0.14+0.16+...+0.88
= ﹙ 0.1+0.9﹚*9/2+﹙0.12+0.88﹚*39/2
=4.5+19.5
=24

12.56+2.8-8.56,15.75+3.59-0.59+14.25,97+365+10

6.8 33 472

The solution of equation 0.3 (X-9) = 12.75 is x = 51.5______ ．

0.3（x-9）=12.75，0.3（x-9）÷0.3=12.75÷0.3，            x-9=42.5，          x-9+9=42.5+9，              X = 51.5.51.5 = 51.5

（ ）：8=12/（ ）=9÷（ ）=0.75

（ 6）：8=12/（16 ）=9÷（12 ）=0.75

x: 75 = 4 / 3:1 / 9

x: 75 = 4 / 3:1 / 9
1 / 9 * x = 0.75 * 4 / 3 (the product of external terms equals the product of internal terms)
x=0.75*4/3*9
x=9

9/（）=0.75=（）：8=12/（）=（）%

9/（12）=0.75=（6）：8=12/（16）=（75）%

75 = () of () = () of 9 = () of ()

0.75 = (3 of 4) = (9 of 12) = (3) / (4)

0.9 + (7 / 8.75)=

1

In 0 &; 3,1,2,5 / 8,4,10,11,) is an integer,) is an odd number,) is an even number,) is a prime number,) is a composite number

1. 2,4,10,11 are integers, 1,11 are odd numbers, 2,4,10 are even numbers, 2,11 are prime numbers, 4,10 are composite numbers

(- 2) ^ 0 - (- 1 / 2) ^ - 4 + (0.1) ^ - 1 + (1 / 3) ^ - 2 &; (1 / 2) ^ 0

Solution
simple form
=1-(-2)^4+(1/10)^-1+3²×1
=1-16+10+9
=4