[填空题]
A 50-year-old man usaay a*a e4 f l()w+rpzmn:i52bkv 1xw o*1mn)hes $+2.5-diopter$ lenses to read a newspaper 25 $cm$ away. Ten years later, he must hold the paper 35 $cm$ away to see clearly with the same lenses. What power lenses does he need now in order to hold the paper 25 $cm$ away? (Distances are measured from the lens.) $P_2$ = + D
