Correct calculation of assets profit and loss

Question

I would like to make some profit and loss calculations based on the market prices.

Scenario 1 (profit):

1. Given a crypto is worth $1500.
   I've made a purchase for $100.
   I've got 0.01666666666666572 (formula: 100 / 1500) of crypto asset.
2. Now a crypto price is worth $1505.55.
   I've decided to sell all of my crypto assets (0.01666666666666572) for actual price.
   Now I have $100.37 (formula: 0.01666666666666572 * 1505.55).
   I've made $0.37 (formula: 100.37 - 100) of profit.

Question 1: Is it calculated correctly ?

Scenario 2 (loss):

1. Given a crypto is worth $1500.
   I've made a purchase for $100.
   I've got 0.01666666666666572 (formula: 100 / 1500) of crypto asset.
2. Now a crypto price is worth $1494.45.
   I've decided to sell only a $12 worth of crypto for actual price.
   formula: 0.01666666666666572 * 1494.45 gives me 24.907499999998585 number, which I believe is totally wrong.

Question 2: How do I calculate a loss in that case ?
Question 3: How do I calculate how much assets I have now ?

Answer 1

Your number of units is wrong. $\frac{100}{1500}\approx 0.0666666666667$. You should not have the $1$. Your multiplication to get the sale value in the profit case is also wrong. If you multiply $0.0666666666666572 * 1494.45=99.63$ you will find you lost $0.37$

For question 3, you calculate the number of units you sell by dividing the number of dollars by the dollars/unit. You then subtract that number of units from the number you started with. As the price has not changed much, you should sell about $1/8$ of what you started with, leaving $7/8$