R For Regrouping (A To Z Challenge)

Regrouping!  Sometimes it goes past times other names but this is a term ofttimes used inward subtraction.  Borrowing is besides a mutual refer for it.  Both are appropriate.

The give-and-take regrouping would hateful putting the numbers inward unlike groups.  In the work below I am regrouping the lay out 22 to locomote 10 too 12, but since the 1 is inward the tens house y'all only write the digit 1.

Borrowing is when y'all intend of each digit inward their place.  The ones house borrows from the tens place...

It's overnice to know how to produce problems on paper, but mental math shouldn't locomote discounted since it is much faster (but I know some teachers can't stand upward it because at that topographic point is no 'work' shown).  But how to mentally intend of this work is y'all accept 22 too since nine is around 10 y'all know 22 minus 10 is 12, but it was entirely minus nine too hence y'all accept i to a greater extent than than that, 13.

Which agency is your favorite agency to solve problems amongst ii digits--writing it downwardly or doing it mentally?