Dana find the sum 346 421 152 for numbers 13a-13d, select yes or no to tell dana when to regroup

To add and get the sum 
  346   
  421
+152

We start on the ones place 6 + 1 + 2 = 9, the sum of the digits in the ones place is not up to 10, we will not regroup this ones place.

So, basically the answer to 13a is NO.
Since we are not able to regroup the ones place there is no regrouped tens to add, therefore the answer to 13b is also NO.

Next is the tens place, 4 +2 +5 = 11, the sum of the digits in the ones place is up to 10 so we regroup the tens place.

Thus, the answer to 13c is YES.

Since, we regrouped the ones place, we add the regrouped hundred, thus the answer to 13d is YES.

Finally, for the hundred place, 1 + 3 + 4 + 1 = 9

Therefore, the sum of 
    346
    421
+  152
is 919