precision
Use estimation when an approximate answer is acceptable.
4 x 0.8 = 3.2
Estimation is a quick of working out roughly what the answer is
Close to what it should be
Estimate 3.99 as 4. The answer will be one less than 4 + 0.84
precision * * * * * For reasonableness you only use estimation.
estimation
With a rough estimation.
you can use it to check an answer
a reasonable estimation is 3.75 x 10-3 m3
Use estimation when an approximate answer is acceptable.
To check your multiplication, you can use the inverse operation: division. Divide the product by one of the original factors; if the result equals the other factor, your multiplication is correct. Another method is to break down the multiplication into smaller parts using the distributive property and then add the results. Additionally, you can use estimation to see if the product is reasonable.
to use your head and explain what you solved
4 x 0.8 = 3.2
Estimation is a quick of working out roughly what the answer is
Close to what it should be
Estimate 3.99 as 4. The answer will be one less than 4 + 0.84