Respuesta :

Assuming you meant 6 x 198... Do a mental sum for 6 x 200 (1200) then subtract 6
-6 x 2 + 6 x 200. Since you want to find out 6 multiplied by 198 the easiest way (for me) would be to round it and then substract 12 since 200-198 is equal to 2 and 6 x 2 is equal to 12