Give the step-by-step reasoning process and then the final answer. Elsa started the day with 40 marbles. At breakfast, she lost 3 marbles while playing. At lunchtime, she gave her best friend Susie 5 marbles. In the afternoon, Elsa's mom bought her a new bag with 12 marbles. Susie came back and gave Elsa twice as many marbles as she received at lunch. How many marbles did Elsa end the day with?
Elsa had 40 marbles - 3 - 5 = 32 marbles. Elsa then gained 12 marbles + 32 = 44 marbles. At dinner Elsa received 2 * 5 marbles from Susie = 10 marbles. In total Elsa had 44 marbles + 10 = 54 marbles.
The final answer: 54.