A teacher gives students the following math problem to solve: (4.20 – 1) × 5.6 Jo solves the problem with a calculator.

Bella solves the problem without a calculator.

Which statements are true? Check all that apply.

Jo’s method is more efficient because there are multiple decimal operations to perform.
Bella’s method could be used if she wanted to use estimation to check the reasonableness of Jo’s calculations.
Jo’s method is more efficient because some of the calculations cannot be done quickly by hand.
Bella’s method is more efficient because calculators should never be used in school.
Bella and Jo can both get the right answer to the problem.