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.
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!
