A length of 7/8cm is divided equal parts(1).what is the length of each parts ?(2)How much is one division differ from 1/8 ?

The total length is $\frac{7}{8}$ cm. The problem states it is divided into "equal parts(1)". We interpret "(1)" as meaning it is divided into 1 part.
The length of each part is the total length divided by the number of parts.

$$\text{Length of each part} = \frac{7}{8} \text{ cm} \div 1 = \frac{7}{8} \text{ cm}$$

"One division" refers to the length of each part calculated in Step 1, which is $\frac{7}{8}$ cm.
To find the difference, we subtract $\frac{1}{8}$ cm from the length of one division.

$$\text{Difference} = \frac{7}{8} \text{ cm} - \frac{1}{8} \text{ cm}$$ $$\text{Difference} = \frac{7-1}{8} \text{ cm}$$ $$\text{Difference} = \frac{6}{8} \text{ cm}$$

Simplify the fraction:

$$\text{Difference} = \frac{3}{4} \text{ cm}$$

The length of each part is $\boxed{\frac{7}{8} \text{ cm}}$.
One division differs from $\frac{1}{8}$ cm by $\boxed{\frac{3}{4} \text{ cm}}$.