Oral arithmetic means calculating with your heart, without writing, calculating in your head, and then reporting (writing) the results.

Written calculation is the process of writing on paper with a pen, also called calculus.

Such as oral calculation (direct writing results):

1) 200×30= 2) 42×4= 3) 63×7= 4) 230×20-46=

Such as calculation problems (calculation outside the formula, write the necessary process):

1),

408- 12×24

= 408 - 288

= 120

2),

(46+28)×60

= 74 x 60

= 4440