Divide and Conquer!

The standard algorithm for division may work for you...

DIVIDE

MULTIPLY

SUBTRACT

BRING DOWN

CHECK!

BUT, I have two new strategies that give you a little more freedom with numbers!

You can choose numbers without having to be so precise with each step of the process. 

Suppose that we want to solve the equation 

324 ÷ 2

First, draw a box with the dividend on the inside and the divisor on the outside.

Then, think in multiples to find a number that is close, but does not go over.
Think 10s, 100s, 1000s!

2 x 100 = 200

Subtract and write the answer in the next box.

Repeat until you are left with a number that is smaller than the divisor.

Let’s take a look at one more example. 

In this example, we will solve 

453 ÷ 4

Draw a box with the dividend on the inside and the divisor on the outside.

Think in multiples to find a number that is close, but does not go over.

Think: 10s, 100s, 1000s!

Think 2s and 5s!

Subtract and write the answer in the next box.

Keep going until you are left with a number that is smaller than the divisor.

When all is said and done, there is a 1 left over...

that's your REMAINDER! 

113 r 1    or     113 1/4

The area model strategy works with 2-digit divisors too! 

Here's an example from page 20 in your Math Activity Book:

Step 1: Think of a few easy X facts for the divisor.

Step 2: Subtract from the dividend an easy multiple of the divisor (e.g. 100x, 10x, 5x, 2x). Record the partial quotient in a column to the right of the problem.

Step 3: Repeat until the dividend has been reduced to zero or the remainder is less than the divisor.

Step 4: Add the partial quotients to find the quotient.

Let’s solve

679 ÷ 5

Click on the images above for a closer look.

Visit Shelly Gray's math website for the videos above and many other helpful math lessons! 

Multi-Digit Multiplication: 3 Strategies

There are many ways to solve multi-digit multiplication problems. Choose the strategy that works with your brain! Here are three of them...

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No matter which strategy we use, the solution remains the same!

427 x 24 = 10,248

If you do not have your X Facts memorized, 5th grade math can take a long time to calculate. I would suggest gluing a Multiplication Chart onto the inside of your Math notebook cover. That way you can refer to it all year.

[click here for a printable X Chart]

  
Here are a few sites that may help with multiplication...

X GAMES!

Partial Product Jeopardy

The Amoeba Multiplication Game

multiplication.com

Timez Attack

  

Keep up the great work, kids!

The Power of Ten

Using exponents is an efficient way to write numbers that have a few too many zeeeeeros.

The exponent (or power) tells us how many zeros are in the number when the base number is 10.

The image below has a place for everything with everything in its place. The base can be any whole number, but today we are only focusing on the POWERS of TEN!

Here are the vocabulary words for this lesson: 

powers of ten

base number 

exponent

Click the image below for a catchy Powers of 10 song! 

Powers of 10 Song Lyrics:

Chorus

To find the power of ten

Look at the exponent

Take your pencil and then

and write that many zeros, let’s do it again

To find a power of ten

Look at the exponent

Take your pencil and then

Multiply that many tens

The base number is 10

2 is the exponent

10 to the second means 10 x 10

This power of ten is 100

Again the base number is 10

but now 3 is the exponent

it equals 10 x 10 x 10

The third power ten is 1000

The base number is 10

4 is the exponent

it's 10 x 10 x 10 x 10

The fourth power is 10,000

Again the base number is 10

5 is the exponent

write five tens and multiply them

and you’ll get 100,000

With a power of ten we can multiply or divide

Dividing slides left, multiplying slides right

The powers the number of places…

Slide the point that number of spaces

One hundred five and nine thousandths

Times ten to the third, the three represents

The decimal point sliding right three times,

The products one hundred five thousand, nine.

Now let’s divide by ten to the third

Slide three places left, or in other words

This number is now one thousand times less -

POWERS OF TEN ARE THE BEST

Using powers of ten is the norm

When writing numbers in expanded form

Split the values apart bit by bit

To see the value of every digit.

Geometry

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Polygon Game

Polygon Mini-Lesson

Practice Measuring Angles

Drawing Angles Game

Alien Angles Game

October STEM Challenge

This month we are going to design catapults that will FLING autumn-ish projectiles 6 feet or more!

Catapults use weights and levers to send large rocks or other things into the air. They were commonly used as weapons during the Middle Ages. Catapults do not throw as far as modern weapons do and are not useful in modern warfare.

During the Medieval Period, catapults were used as weapons to throw rocks or other things such as hot tar, that would cause damage to something else. Often, catapults were set on higher ground or on castle towers to let them shoot farther. They shot rocks to break castle walls or hot tar to set the target on fire.

Let's design mini-catapults!

Use items from around your house to design a free-standing mini catapult that will launch October themed projectiles farther than 6 feet! Projectiles can be anything related to fall - apples, mini pumpkins, acorns, fall-colored pompoms, Halloweeny stuff, etc.

Send Mrs. Sol pictures or movies of your experiment to share in class.

DUE OCTOBER 18