4 x 0.8 = 3.2
To use estimation to check an answer, first round the numbers involved in the calculation to make them simpler. Then perform the estimated calculation and compare the result to your original answer. If the estimate is significantly different from your original answer, it may indicate that there is an error or that the original answer needs to be re-evaluated. This method helps verify the reasonableness of the final answer.
Close to what it should be
You use compatible numbers.
precision
56x34
precision * * * * * For reasonableness you only use estimation.
4 x 0.8 = 3.2
To use estimation to check an answer, first round the numbers involved in the calculation to make them simpler. Then perform the estimated calculation and compare the result to your original answer. If the estimate is significantly different from your original answer, it may indicate that there is an error or that the original answer needs to be re-evaluated. This method helps verify the reasonableness of the final answer.
Close to what it should be
You use compatible numbers.
precision
It is extremely important, because everyone(including me) makes simple mistakes and sometimes needs to check.
Multiplication
With multiplication.....
you could have done something wrong on the calculator !
so when you find your answer you can check it by using multiplication.