I completely agree, i went to a shop the other day and the poor assistant couldn't subtract $7 from $10 and needed to double check. It must be hard not being able to do simple addition and subtraction without a device. I understand that Apps can be useful for those who have poor numeracy, literacy, and for checking homework answers.
I have never used a App to check answers before but now feel the need when homework is marked incorrectly. Unbelievably when I sought clarification another wrong answer was provided! I have since looked for an App an there seems a lot out there but I don't know which is the best,
Can anyone tell me the correct answer using an App? Which App did you use? Thanks!