Mathematics for IGCSE & O level - Using A Calculator (Section 3 - No. 38)
If the answer is not close to the estimated answer, what should be done?
Follow the order of operations.
Check for any errors.
Estimate to check the answer.
Try to re-do the problem with a different method.
स्पष्टीकरण
All these options will help solve the problem, and check for any errors.