Parents SHOULDN'T avoid sharing their own mistakes with children.
Mass is an amount of substance present in a body. mass is measure with the help of triple beam balance. the unit of mass are kilogram, gram etc.
To find the acceleration, use the formula: force= mass x acceleration.
12.5 N = 10 x Acceleration
Acceleration = 12.5 / 10
Acceleration = 1.25
Hope this helps :)