90дм 4мм-8 м 34см=

To solve this problem, we will convert the lengths to the same unit of measure for accurate subtraction.

Let's convert everything to centimeters (cm) since that's the smallest unit given that can include both millimeters and decimeters.

1 decimeter (дм) = 10 centimeters (см) 1 meter (м) = 100 centimeters 1 millimeter (мм) = 0.1 centimeters

First, we'll convert 90 дм to см: 90 дм = 90 * 10 см = 900 см

Then we'll convert 4 мм to см: 4 мм = 4 * 0.1 см = 0.4 см

Now add them to get a single length in см: 900 см + 0.4 см = 900.4 см

Now convert 8 м to см: 8 м = 8 * 100 см = 800 см

And convert 34 см to см (which is already in см, so no conversion is needed): 34 см = 34 см

Now subtract the second length from the first: 900.4 см - (800 см + 34 см) = 900.4 см - 834 см = 66.4 см

So, the result of the subtraction is 66.4 см.