When the two numbers have an answer that is greater than or equal to ten.
25
no
how
With addition, you need to regroup in the event that there are more than 10 ones or 10 tens. In a subtraction, you must regroup whenever there are insufficient ones or tens to subtract.
8 tens.
No.
Yes.
1 tens and 2 0nes
When the squad leader deems it necessary to align, it means there is a need to regroup.
500+10+6 = 516
78 can be regrouped into 6 tens and 18 ones.
(3*10)+(9*1)=39