Adding is fairly simple.If we were doing 213+908,first we add the ones,which give us 11.We keep the 1,and put the one in the tens place of 3+8 and add it to the tens place of the addition problem.Our ones place is 1. In our tens place we have 1+1+0. The first one came from our carry-over.Our ones place and tens place is 21.Our final place is 2+9.That gives us 11.We do no carry-overs because there are no place values to the left of the 2 and 9.That is on how you add.
Subtract: 490-321.Subtraction is the opposite of addition.490-321 is calculated by these steps:
1.Do 0-1.Since you can't do that,9-1=8,10-1=9.
2.Do 8-2.8-2=6.
3.Do 4-3.4-3=1.Our answer is 169.
Say we are multiplying 16×38.First,we would do 16×8,giving us 128.Next,we do 16×30 on the next line,which is 480.Now the problem looks like this after the lat step,adding 128 to 480,with the answer:
16
×38
______
128
+480
______
608.
That is on how you do 2-digit by 2-digit multiplication
Division is the opposite of multiplication,and is repeated subtraction.Say we were doing 188÷3.First we would see if 1 divides into 3 evenly.No.Then we see if 18 divdes into 3.Yes,it does.18÷3=6.Then we do 8÷3,giving us 2,with a remainder of 2.Our answer is 62R2 (note thar R means remainder).That is how you do division.