Please help with this math problem?

You own 405 shares of stock A and 780 shares of stock B. During one week, A increases by $3.05 per share, while B loses $1.24 per share. How much did the value of your investment change?

thank you!

Steve A2014-05-12T13:54:00Z

405($3.05) - 780(1.24) = $268.05

David2014-05-12T13:54:11Z

405 * 3.05 - 780 * 1.24
1235.25 - 967.2
268.05

it increased by $268.05