So you went cheap, and bought a super cheap calculator. But is it any good? Does it actually know how to do math? Does it know the correct order? Does it show errors when failing to compute?
sqrt(2) = 1,414213562373095
sqrt(2) * sqrt(2) = 2
1 / 9 = 0,1111111111111111
1 / 9 * 9 = 1
7 * 7 = 49
5 + 2 x 5 = 15
6 × (5 + 3) = 48
5 × 2^2 = 20
1 / 0 = "error"