We using Base ten to make the numbers in the sentence. We count the ones first and record the answer, then the tens. 

We progress to drawing the Base Ten using a line to represent a ten and a circle to represent the ones. 

When using Base Ten to subtract a number, we make the first number with Base Ten then we subtract the second number by removing the Ones first followed by the Ten's to find the answer. 

We progress to drawing Base Ten for our subtraction and crossing off the Ones from the number we are subtracting, we then circle the remaining Ones. We then do the same for the Ten's.