YouTube Videos
I have a channel on YouTube, shockingly called "Dr. Karen's Math Hacks". Herer are the videos from that channel sorted by subject matter.
Adding and Subtracting
Adding and Subtracting In Your Head - Part 1
Adding and Subtracting In Your Head - Part 2
Subtracting Without Borrowing
Adding Columns
Subtracting From Large Round Numbers
Subtracting Large Numbers
Adding and Subtracting Numbers that end in 7, 8, or 9
Multiplying and Dividing
The Multiplication Table
Multiplying 2-Digit Numbers
Don't Multiply Zeros
3 Ways to Multiply by 9
Long Division Review
Can I Divide By...
Divide by 2
Exercises - Cutting Things in half
Multiply and Divide by 5
Exercises - Multiply by 5
Exercises -      Divide by 5
Divide First
Divide By Parts
Divide by Simplifying
Taking the "long" Out of Long Division
Tricks with Numbers That Multiply to 100
Multiplying Numbers that End in 7, 8, or 9.
Moving 2s Around
Moving 10s around
Dividing by Small Numbers
Averages
Taking an Average
Averaging using Subtracting
Averaging using Differences
Averaging Using Packets
Working with Multiple Units
Borrowing with Multiple Units
Subtracting Without Borrowing - Multiple Units
Fractions
Thinking About Fractions
Fractions and Mixed Numbers
Adding and Subtracting Fractions
Adding Fractions Graphically
Subtracting Fractions Graphically
Fraction-Decimal Conversions
Multiplying Mixed Numbers and Fractions
Multiplying Whole and Mixed Numbers
Subtracting Mixed Numbers
Dividing a Mixed Number by a Whole
Why We Invert and Multiply
Dividing Fractions and Mixed Numbers by Whole Numbers
Dividing Fractions by Turning Them Into Whole Numbers
Multiplying Mixed Numbers Using the FOIL Method
Multiplying two Mixed Numbers
Ratios and Percentages
Solving Ratios with Relationships
The 10% Method
Using The 10% Method to Find a tip
Solving Percentage Problems Using Substitution
Simplifying Ratios
Geometry
Perimeter, Area, And Volume
Surface Area VS Volume
Area and Circumference of Circles
Multiply by Pi using the 10% Method
Story Problems
Story Problems
Multiplying Fractions - Part 1
Units Tell You What To Do
Is it a Ratio Problem?
Multiplying Fractions - Part 2
Problem-Solving and Misc...
Scientific Notation
Rearranging Equations
Reuse/Recycle Your Math
Converting Cups, Pints, Quarts, and Gallons
Simplifying Square Roots
Working with Negative Spaces
Finger Trig
Airplane/Timezone Math
Squaring Numbers that end in 5
Handling Exponents