Not to get the calculation results.

But through calculation to establish the abstract concept of numbers.

Understand the carry property of decimal numbers

Familiar with the rules of addition and subtraction

Do not advocate quick calculation

Otherwise, it is meaningless.

Our education is always great.

.

There is no quick calculation for the addition and subtraction of two digits.

If you want to hurry.

Then ask a robot with hearing to answer.

Or use speech recognition software to calculate.

This is the fastest.