How you can avoid silly mistakes in Mathematics.
Maintain a strategic framework.
Do your calculations on paper.
Break it down into smaller steps rather than attempting to achieve too much in one go.
To get high concentration, you can practise some simple meditation.
Read the question carefully every time.
We get faster and more assured when we practise answering various kinds of questions.
Always double-check your answers.
Making use of shortcut techniques that reduce calculation such as basic arithmetic techniques given in vedic maths.