8
(1) ∵ P+Q={a+b|a∈P,b∈Q},P={0,2,5},Q={1,2,6},∴ 当a=0时,a+b的值为1,2,6;当a=2时,a+b的值为3,4,8;当a=5时,a+b的值为6,7,11,∴ P+Q={1,2,3,4,6,7,8,11},∴ P+Q中有8个元素.
8
(1) ∵ P+Q={a+b|a∈P,b∈Q},P={0,2,5},Q={1,2,6},∴ 当a=0时,a+b的值为1,2,6;当a=2时,a+b的值为3,4,8;当a=5时,a+b的值为6,7,11,∴ P+Q={1,2,3,4,6,7,8,11},∴ P+Q中有8个元素.