Apparently in 2012, the UK government announced it intended to ban the use calculators from primary classrooms that students use them too much.

Research was then conducted in response to this which found little difference in performance tests whether students used calculators or not. An earlier US study had found the same: the calculator had no positive or negative effects on the attainment of basic maths skills.

Since the 1980s we have had access to calculators of various types. including computers and smartphones but as it appears it my not have a lot of harm as it is good.

http://theconversation.com/weapons-of-maths-destruction-are-calculators-killing-our-ability-to-work-it-out-in-our-head-44900