Students begin understanding the idea of regrouping (or carrying the one as we learned in school) using base ten blocks. These blocks help students visualize the process and creates a hands-on experience with regrouping. 

Renaming a number is just showing that a number can be made in several different ways.  Understanding that 3 tens is the same thing as 2 tens and 10 ones is extremely beneficial when students begin subtraction with regrouping.  ( 30 = 20 + 10)

Now THIS is what we as parents remember from school! Using an algorithm to solve addition problems! This is also where our teachers would say, "carry the one!"  Although students are still "carrying the one" this procedure meant nothing to us.  It was just what we did because we were told to in order to get the right answer.  

Today we call this process regrouping or renaming, so that students understand the procedure and why that process actually works, hence the use of the base ten blocks in the beginning. We are not carrying anything, we are regrouping a part of one number (the tens) into a new place to add like numbers. 

Thankfully, the algorithm looks the same as when we grew up! You might, however, find the regrouped ONE at the bottom of the algorithm, instead of the top.  It's just a visual thing, and completely a preference for some students. 

Like addition students begin understanding the idea of regrouping (or borrowing as we learned in school) using base ten blocks. These blocks help students visualize the process and creates a hands-on experience with regrouping. 

Renaming a number is just showing that a number can be made in several different ways.  Understanding that 3 tens is the same thing as 2 tens and 10 ones is extremely beneficial when students begin subtraction with regrouping.  3 tens = 2 tens AND 10 ones   ( 30 = 20 + 10)

Again, THIS is what we as parents remember from school! Using an algorithm to solve subtraction problems and borrowing from next door! There are a million cute little rhymes and sayings to help students remember the procedure of subtraction with regrouping, but the deep understanding is what we want students to come away with, so they can apply this concept and idea to fractions, decimals, and algebra later on.   

Today we call this process regrouping or renaming, so that students understand the procedure and why that process actually works, hence the use of the base ten blocks in the beginning. We are not borrowing anything, we are regrouping or renaming a number so that the value of the number in each place is enough to actually subtract without using negative numbers.  

Thankfully, the algorithm looks the same as when we grew up! Exactly the same.  You just have to get used to saying regroup the tens and ones, instead of borrow from the ten.