Subtracting Whole Numbers: Subtraction Approaches: Take-Away and Missing Addend
This clip explains that subtraction is used to solve two different types of problems. In the first, we start with some things and remove--or take away--some or all of them. The other approach to subtraction, called the missing addend, "
is like goi...
Subtracting Signed Numbers: Using the Number Line to Subtract Signed Numbers
This clip explains how students can use the number line to more easily understand the subtraction of negative numbers. The clip also points out that one of the reasons signed numbers were invented "
(was so that) we can subtract any two numbers
la...
Subtracting Whole Numbers: Summary: Subtracting Whole Numbers
This clip summarizes how subtraction is used in two types of problems: those in which there's a "take-away" and those in which there's a missing addend. It also reviews the link between subtraction and addition, explaining how addition can be used t...
Subtracting Whole Numbers: Practical Subtraction Problems
This clip looks at how subtraction can be used to determine how much more money is needed to buy something, as well as how many more cars will fit in a parking lot.
Subtracting Whole Numbers: Subtraction Problems May Not Be Rearranged
This clip explains that, while the addends can be rearranged or regrouped in addition without affecting the answer, the same is not true in subtraction.
Subtracting Whole Numbers: Using the Addition Facts in Subtraction
This clip makes the case that "since every subtraction fact is an addition fact in disguise, learning them isn't so hard."
Subtracting Whole Numbers: Borrowing
This clip uses expanded notation to demonstrate the technique known as borrowing in subtracting both two and three-digit numbers.
Subtracting Whole Numbers: Using Columns to Subtract Two-Digit Numbers
This clip explains the use of columns when doing subtraction problems with "larger numbers." With this approach, we subtract "ones from ones, tens from tens (and), hundreds from hundreds."
Subtracting Whole Numbers: Using Addition to Check Your Answers
This clip explains how addition can be used to verify that the answer to a subtraction problem is correct.
Dividing Whole Numbers, Part 2: Comparing Methods of Division
This clip explains that dividing can sometimes be done more quickly for those comfortable with guessing the partial quotient rather than figuring it out. On the other hand, the method known as "long division" offers another approach altogether.