Mammoth Memory

Common core addition

Common core addition - Line addition (or open number line)

This is a method of adding two numbers using small progressive steps along a line.

Line addition example showing how 36 can be added following steps along a line

Example 1

42+27

Step by step of line addition with 42 plus 27

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Step by step

Example 1

42+27

Draw a line across the page with the largest number at the start

Now break down the smaller value in smaller manageable chunks

Write down a running total at every increment intersection

Make an other jump with another manageable chunk from the smaller number

Write another running total at this point it should be 62

Make the last jump adding the last few digits form the smaller number

The final line addition should look like this

Answer: =69

Answer: =69

 

Example 2

419+275

Step by step of line addition with 419+275

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Step by step

Example 2

419+275

Draw a line across the page with the largest number at the start

Now break down the smaller value in smaller manageable chunks

Write down a running total at every increment intersection

Keep incrementing the smaller number into manageable chunks

The new running total in this instance is 689

Increments can be as small as possible such as one so make it an increment.

Keep doing a running total

The final jump is 4 in this instance so draw it on

The final line addition should look like this

 

Answer: =964

 

Example 3

256+137

Step by step of line addition with 256+137

To see how this is broken down 

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Step by step

Example 3

256+137

Draw a line across the page with the largest number at the start

Now break down the smaller value in smaller manageable chunks

Write down a running total at every increment intersection

Add an easy amount, the shorter the value the longer the line will be...

Keep doing a running total

Keep incrementing the next should be 11

The new running total should be 377

Do another 10 jump

The new running total should be 387

Round numbers are easier to add up so a 4 jump would make it easier wouldn’t it?

The new running total should be 391

Add another 3 to the line

The final sum should be 393

Answer: 256+137=393

Answer: =393