First of all, let’s confirm the learning foci that should be acquired when considering the further worksheets.The slide shows the addition and the subtraction problems given in Level B as an example.When students solve the 2-digit+2-digit problem shown on the left by adding each digit, they have to do 1-digit+1-digit addition two times and then handle the carrying.When students solve the 2-digit – 2-digit subtraction shown on the right by subtracting each digit, they have to do 1-digit – 1-digit or 2-digit – 1-digit subtraction two times and then handle the borrowing.(Click) As just described, in Level B, students need to do 1-digit + 1-digit addition, or do subtraction including two digit numbers, a few times in one problem.Therefore, it is important to have student develop their skills to do these kinds of addition and subtraction quickly and accurately by the end of Level A.How do students develop such skills in worksheets?Let’s look at the worksheet structures of Addition sections.