*Contributor: Alison Weiss. Lesson ID: 10600*

Hmmm. What did people use before calculators? How can you solve long problems without one? Use lots of practice to learn to add and subtract large numbers without regrouping (or calculators)!

categories

subject

Math

learning style

Visual

personality style

Lion, Beaver

Grade Level

Intermediate (3-5)

Lesson Type

Skill Sharpener

- Do you need a calculator to add or subtract long numbers?

Try this: 4529 - 2312 =

You certainly do NOT need a calculator to add or subtract!

**ADD**

Let's look at addition first. The key is to write the equation properly so that all the place value positions line up.

So, 2535 + 1454 would look like this:

2 | 5 | 3 | 5 | ||

+ | 1 | 4 | 5 | 4 |

The ones, tens, and hundreds columns are all lined up. Now, we can add.

We always start with the ones!

- So, what is 5 + 4?

2 | 5 | 3 | 5 | ||

+ | 1 | 4 | 5 | 4 | |

9 |

Next, we look at the tens.

- What is 3 + 5?

2 | 5 | 3 | 5 | ||

+ | 1 | 4 | 5 | 4 | |

8 | 9 |

- What comes next?

The hundreds, of course!

2 | 5 | 3 | 5 | ||

+ | 1 | 4 | 5 | 4 | |

9 | 8 | 9 |

Now, the thousands!

2 | 5 | 3 | 5 | ||

+ | 1 | 4 | 5 | 4 | |

3 | 9 | 8 | 9 |

- What if the numbers don't have the same amount of digits, like 2488 + 211?

Line them up, starting with the ones, like this:

2 | 4 | 8 | 8 | ||

+ | 2 | 1 | 1 |

You can pretend there's a zero in the hundred's place, like this:

2 | 4 | 8 | 8 | ||

+ | 0 | 2 | 1 | 1 |

Add just like you did above. Try it now!

Don't reveal the answer until you're done!

- Did you get it correct?

Great!

**SUBTRACT**

You don't need a calculator to subtract long numbers, either!

- Can you do 6846 - 5734?

Let's take this step-by-step!

We're going to rewrite the problem so the bigger number is on top, and make sure all the place value positions line up, like this:

6 | 8 | 4 | 6 | ||

- | 5 | 7 | 3 | 4 |

Now we can subtract. Remember, we always start with the ones!

- So, what is 6 minus 4?

6 | 8 | 4 | 6 | ||

- | 5 | 7 | 3 | 4 | |

2 |

Next, we move on to the tens column.

- What's 4 minus 3?

6 | 8 | 4 | 6 | ||

- | 5 | 7 | 3 | 4 | |

1 | 2 |

Keep going with the hundreds!

6 | 8 | 4 | 6 | ||

- | 5 | 7 | 3 | 4 | |

1 | 1 | 2 |

Now, to finish it off, the thousands!

6 | 8 | 4 | 6 | ||

- | 5 | 7 | 3 | 4 | |

1 | 1 | 1 | 2 |

There you have it!

Just remember to put the bigger number on top, line up your place value positions, start with the ones, and subtract each place value as you move to the left.

Just like with addition, if one number has more digits, pretend there's a zero in the empty spot!

4 | 7 | 8 | 9 | ||

- | 0 | 3 | 2 | 4 |

Now you can add or subtract 4-digit problems. You could even add or subtract 32-digit problems (if you really wanted to!)

Great job learning!

Now, move on to the *Got It?* section, and practice what you've learned!