Distributive Property with Distributive Property with Partial Products Method of Partial Products Method of

MultiplicationMultiplicationMultiplying 2-digit by 2-digit NumbersMultiplying 2-digit by 2-digit Numbers

Don't be Don't be scared!scared!

You can do thisYou can do this

Let's start with a Let's start with a problemproblem

• I know you're a little short I know you're a little short and funny looking...and funny looking...

• But I meant a math problemBut I meant a math problem

• Let's go with 56 x 78Let's go with 56 x 78

Expand your mind, manExpand your mind, man

• Actually, you should put the Actually, you should put the two numbers in expanded two numbers in expanded formform

• 50 + 650 + 6

• 70 + 870 + 8

Set it upSet it up

• So we're multiplying So we're multiplying

• (50 + 6) x (70 + 8)(50 + 6) x (70 + 8)

Equality for Equality for All!All!

Since there are 4 numbers to deal Since there are 4 numbers to deal with...with...

Place 4 equal signs under the Place 4 equal signs under the problemproblem

Order UpOrder Up

• Okay, the commutative Okay, the commutative property does state that property does state that order doesn't matter, but...order doesn't matter, but...

• You should follow a certain You should follow a certain order here because it's easy order here because it's easy to get mixed upto get mixed up

• So let's start with the ones So let's start with the ones place on bottomplace on bottom

Multiply the 8 by both numbers Multiply the 8 by both numbers on topon top

Good idea to go right to leftGood idea to go right to left

Move OverMove Over

• Now let's get to the tens Now let's get to the tens place on bottomplace on bottom

• Write the 70 down by the Write the 70 down by the last two equal signslast two equal signs

Keep the pattern goingKeep the pattern going

• Multiply 70 times the ones Multiply 70 times the ones place on topplace on top

And GoingAnd GoingNow multiply the 70 times the tens Now multiply the 70 times the tens

place on topplace on top

It All Adds UpIt All Adds UpNow add up your partial products to find your final answerNow add up your partial products to find your final answer

So 56 x 78 = 4,368So 56 x 78 = 4,368Here's a picture of your motherHere's a picture of your mother