the answer is -60. this is because the signs implemented in front of numbers give it a sort pattern .
when there are two additions the last number after the positive sign will give a positive number 1 greater than the initial number for example + 5 + 6. Answer afterward will be + 7 and for negative sign eg: - 7 - 8 in the question will give the answer -8 the same number after a negative (-) sign . Hope this helps