Subtracting Signed Numbers: Subtracting a Negative Number From a Positive Number
This clip explains the steps necessary to solve a problem in which a negative number is subtracted from a positive number.
Subtracting Signed Numbers: Subtracting a Larger Number From a Smaller Number
This clip explains the steps necessary to solve a problem in which a larger number is subtracted from a smaller number.
Dividing Signed Numbers: Introduction to Dividing Signed Numbers
This clip explains that the rules for dividing signed numbers are the same as for multiplying signed numbers, "
except, of course, that we divide the absolute values instead of multiplying." When the signs are the same, the quotient is positive. Wh...
Dividing Signed Numbers: Dividing Positive by Positive and Negative by Negative
This clip explains that, when dividing signed numbers, if the divisor and dividend have the same sign, the quotient is positive.
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...
Interpreting Graphs: Distorted Graphs
This clip explains that sometimes a distorted graph may be a more practical way to display data, then provides a number of examples, including a bar graph of U.S. population, a line graph of Federal debt, and a line graph of households with cable te...
Adding Signed Numbers: Adding More Than Two Signed Numbers
This clip explains that the best way to proceed when adding more than two signed numbers is to add all the positive addends and all the negative addends separately, then add the resulting sums.
Adding Signed Numbers: Practical Problems: Temperature and Distance
This clip provides two short exercises, one dealing with temperature changes, the other with changes in direction, to illustrate how to solve practical problems involving the addition of signed numbers.
Adding Signed Numbers: Using Parentheses in Adding Signed Numbers
This clip explains the use of parentheses to eliminate the confusion that might arise if two signs are written next to each other, as when adding a negative number. The clip notes that we don't run into this problem with positive numbers, because in...
Multiplying Signed Numbers: General Rule for Multiplying Signed Numbers
This clip explains that if two factors with the same sign are multiplied, the product is always positive. When two factors with different signs are multiplied, the product is always negative.