Mammoth Memory

Common core subtraction - Number line subtraction

Again common core subtraction is using addition instead. Add up from the smaller number to the bigger number.

 Subtraction = Addition

To subtract using the common core we use the same method as addition but the other way around

Yes Really! Subtraction is addition.

 

Example 1

`32-12`

Start with the smallest number and add, Yes add!

    `3`
  `+` `5`
  `+` `10`
  `+` `2`
    `20`

 

To see this step by step

Press Here

Common core subtraction - Number line subtraction step by step

Example 1

`32-12`

Step by step, draw a line on the page

Start with the smallest number in the sum and start to add in small chunks, you must write the amount you have jumped on the top of each increment

Begin to write down the running total

Your jumps can now be increased

Begin to write down the running total

Make it easy and jump with tens

Begin to write down the running total

Do the final sum with whatever is left

The running total at the end should equal the larger number of the sum

To get the main amount you have to add together the increments you have just made along the line

Answer: `32-12=20`

 

Answer: `32-12=20`

 

Example 2

`243-87`

Start with the smallest number and add, Yes add!

 

    `3`
  `+` `10`
  `+` `100`
  `+` `43`
    `156`

 

To see this step by step

Press Here

Common core subtraction - Number line subtraction step by step

Example 2

`243-87`

Step by step, draw a line on the page

Start with the smallest number in the sum and start to add in small chunks, you must write the amount you have jumped on the top of each increment

Begin to write down the running total

Your jumps can now be increased

Begin to write down the running total

Make it easy and jump with tens

Begin to write down the running total

Do the final sum with whatever is left

The running total at the end should equal the larger number of the sum

To get the main amount you have to add together the increments you have just made along the line

Answer: `243-87=156`

 

Answer: `243-87=156`

 

Example 3

`264-128`

Start with the smallest number and add, Yes add!

    `2`
  `+` `70`
  `+` `60`
  `+` `4`
    `136`

 

To see this step by step

Press Here

Common core subtraction - Number line subtraction step by step

Example 3

`264-128`

Step by step, draw a line on the page

Start with the smallest number in the sum and start to add in small chunks, you must write the amount you have jumped on the top of each increment

Begin to write down the running total

Your jumps can now be increased

Begin to write down the running total

Make it easy and jump with tens

Begin to write down the running total

Do the final sum with whatever is left

The running total at the end should equal the larger number of the sum

To get the main amount you have to add together the increments you have just made along the line

Answer: `264-128=136`

Answer: `264-128=136`

 

OR

 

Start with the smallest number and add, Yes add!

    `100`
  `+` `30`
  `+` `2`
  `+` `4`
    `136`

 

To see this step by step

Press Here

Common core subtraction - Number line subtraction step by step

Example 3

`264-128`

Step by step, draw a line on the page starting with the smallest number

Step by step, draw a line on the page starting with the smallest number

There are large numbers involved here so you can afford to make large jumps

Begin to write down the running total

You have done the largest jump needed so start to reduce the jumps to make it easier

Begin to write down the running total

Only make small steps now continuing to make it easier for yourself

Begin to write down the running total

Make the final jump to insert the remaining digits

Start with the smallest number and add, Yes add!

Answer: `264-128=136`

More Info