As a Math lover and as well as a Math teacher, I am convinced that excessive use of calculators for simple calculations cause over dependence on them. This undermines the mind’s ability to do very simple additions. This causes a lot of discomfort for the students who eventually start to hate math as a subject.
Just as nature took away the tail as humans evolved from a monkey, as it was not used (even joints of the body atrophy when not used / exercised), so would the brain’s ability to do simple math atrophy if we become overly dependent on calculators.
Encourage your kids and students to compute mentally. Let’s get back our brains!