Math Lessons and Notes

It is very important that in addition to weekly "extra work" in Mathematics, students are responsible for practicing their multiplication and division facts.

It is expected that students will be fluent with their facts and have automaticity. Students are assessed formally and informally on a weekly bases.

Math in Focus - Grade 4

Khan Academy Resource Videos

Chapter One:

Finding place valueSal finds the place value of 3 in 4356.

Writing a number in expanded formSal writes 14,897 in expanded form.

Writing a number in standard formLearn to write six hundred forty-five million, five hundred eighty-four thousand, four hundred sixty-two with numbers.

Regrouping (borrowing) twice exampleSal using regrouping to subtact 9601-8023.

Worked example: Subtracting 3-digit numbers (regrouping from 0)Sal has to borrow from a 0 to subtract 301-164.

Chapter Two:

Rounding to nearest 100Learn to use a number line to round 3-digit numbers to the nearest hundred.

Prime numbersPrime numbers are numbers that are only divisible by themselves and 1. Learn more about their properties, and see some examples.

Finding factors and multiplesSal uses divisibility rules to determine if numbers are factors of 154 and then finds multiples of 14.

Rounding to nearest 10 and 100Learn to round up to 4-digit numbers to the nearest ten and hundred.

Recognizing prime and composite numbersCan you recognize the prime numbers in this group of numbers? Which are prime, composite, or neither?

Greatest common factor explainedHere's a nice explanation of greatest common factor (or greatest common divisor) along with a few practice example exercises. Let's roll.

Finding factors of a numberSal finds the factors of 120.

Chapter Three:

Multiplying 1-digit numbers by 10, 100, and 1000Lindsay finds a pattern from multiplying 1-digit numbers by 10, 100, and 1000.

Multiplying: 2-digit by 1-digit (regrouping)Sal solves 6x37.

Multiplying with area model: 78 x 65Sal uses an area model to multiply 78x65.

Multiplying 2-digit by 1-digitLearn to multiply a 2-digit number by a 1-digit number without regrouping. In this video, we will multiply 32x3.

Multiplying 3-digit by 1-digit (regrouping)Learn to multiply a 3-digit number by a 1-digit number using regrouping. In this video, we will multiply 7x253.

Multiplying 2-digit numbersLearn to multiply two-digit numbers. In this video, we will multiply 36 times 27.

Multiplying 3-digit by 1-digitLearn to multiply a 3-digit number by a 1-digit number without regrouping. In this video, we will multiply 4x201.

Division using place valueSal uses an understanding of place value to divide 5600÷8 and 846÷2.

Multiplying with area model: 16 x 27Sal uses an area model to multiply 16x27.

Chapter Six:

Intro to fractionsSal divides wholes into equal-sized pieces to create unit fractions.

How to add fractions that have different denominatorsTo solve this problem, we need to find the least common multiple to get at the common denominator. Can you help? We bet you can!

Multiplying unit fractions and whole numbersSal multiplies 1/2 x 5 using repeated addition and fraction models.

Cutting shapes into equal partsLindsay figures out if 4 pieces of pie are each equal to 1/4 of the pie.

Subtracting fractions with like denominatorsSal subtracts 8/18-5/18.

Decomposing a mixed numberSal uses fraction models to decompose 2 1/4.

More about fractionsSal shows fractions as parts of a whole and parts of a group.

Fraction word problem: spider eyesSal solves a fraction word problem about spider eyes. The fractions have common denominators.

Intro to line plotsA line plot is a graph that displays data using a number line. To create a line plot, first create a number line that includes all the values in the data set. Next, place an X (or dot) above each data value on the number line. If a value occurs more than once in a data set, place an Xs over that number for each time it occurs.

Fractions on a number lineLearn to graph and locate fractions on a number line.

Visualizing equivalent fractionsSal uses fraction models to show equivalent fractions.

Chapter Seven:

Intro to decimalsSal introduces decimal numbers and understanding place value to the right of the decimal.

Graphing tenths from 0 to 1 Lindsay graphs 0.6 on a number line.

Rewriting tricky fractions to decimalsLearn to convert the fraction, 17/93 to a decimal.

Decimals as wordsSal writes 0.17 and 40.03 in words. He also writes twenty-four hundredths using numbers.

Visually converting tenths and hundredthsSal rewrites 8/10 with a denominator of 100.

Writing decimal numbers shown in gridsSal uses grid diagrams to determine what decimal is represented by a shaded area.

Decomposing hundredths on number lineSal decomposes 26/100 into tenths and hundredths using a number line.

Decimal place valueIntroduction to decimal place values and the value of decimal digits

Decomposing hundredths Sal decomposes 47/100 into tenths and hundredths.

Chapter 8:

Adding decimals: 9.087+15.31Sal solves 9.087+15.31 using the "standard algorithm".

Adding decimals: 0.822+5.65Sal solves 0.822+5.65 using "standard algorithm".

Regrouping with decimals: 21.3Sal regroups 21.3 into various addition problems.

Regrouping with decimals: 86.93Sal regroups 86.93 by its place values.

Chapter 9:

Angles: introductionTwo rays that share the same endpoint form an angle. Learn about angles and the parts of an angle, like the vertex.

Naming anglesSal names angles based on their vertex and endpoints.

Chapter 11:

Recognizing shapesRecognizing shapes

Intro to area and unit squaresSal covers figures with square units to find their area.

Parallel & perpendicular linesParallel lines are lines in a plane that are always the same distance apart. Parallel lines never intersect. Perpendicular lines are lines that intersect at a right (90 degrees) angle.

Chapter 12:

Perimeter & areaPerimeter is the distance around the outside of a shape. Area measures the space inside a shape. Learn how to calculate perimeter and area for various shapes.

Metric system: units of distanceSal discusses metric units of length or distance such as millimeter, centimeter, meter, and kilometer.

U.S. customary units: distanceSal discusses US customary units of length or distance such as inch, foot, and yard.

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