**Or**

*"What's the takeaway going to be from this?"**For a high school number sense test, it can't get much more basic than subtracting whole numbers. But this concept showed up 11 times this year (6 times as question #1 and 5 times as question #2). It's important that we get these types of questions right--we don't want to waste valuable points (or valuable time) by skipping over this important lesson. So, here we go:*

**"Why all the negativity?"****Number Dojo Level: 6**

**Subtracting Whole Numbers**

When you see a subtraction problem, you will be given a

**minuend**and a

**subtrahend**.

*What's the*The difference is that the minuend comes first :). Also, the difference is the result you come up with when you subtract the subtrahend from the minuend.

**difference**?**The Old Way**

Most of us spent the subtraction portion of our childhood looking at numbers that were aligned vertically, with the units digits in a perfect column, and the rest of the digits arranged similarly. Here, the minuend is on top, and the subtrahend is below it:

**2016**

?

__- 602__?

**The Number Sense Way**

Unfortunately, those were the good old days. When you see a subtraction problem on a number sense test, it will always be written horizontally, with the minuend in front of the subtrahend:

**2016 - 602 = _________**

*Or, to put it more simply,*

**"Which is bigger--the minuend or the subtrahend?"**

**"Am I going to get a negative number for my answer?"**This will determine where you start your calculation. If you are subtracting a bigger number from a smaller one, you need to start with the bigger number, calculate the difference, and then add a "minus sign" in front to make it negative.

Then, subtract the units digits, regrouping when necessary. (If you haven't noticed, I prefer to call it "regrouping" than "borrowing."

**I am highly averse to debt.**) Move on to the tens digits, then the hundreds, etc. Like many types of problems in mathematics, it seems to be quicker moving from right to left.

**Example 1: 2016 - 602**

- Notice the number in front is bigger, so start with it.
- 6 - 2 =
**4**. 1 - 0 =**1**. 0 - 6 (STOP and realize you need to regroup). 10 - 6 =**4**. 2 (NO--1 because you just regrouped). 1 - (an implied) 0 =**1**. The difference is**1414**.

**Example 2: 867 - 5309**

- Notice the number in front is smaller, so start with the 2nd number.
- 9 - 7 =
**2**. 0 - 6 (STOP and realize you need to regroup). 10 - 6 =**4**. 3 (NO--2 because you just regrouped). 2 - 8 (STOP and regroup again). 12 - 8 =**4**. 5 (NO--4 because you just regrouped). 4 - (an implied) 0 =**4**. The difference is 4442. - Don't forget to add the minus sign to get
**-4442**.

**Example 3: 1357 - 2468**

- Start with the (bigger) 2nd number. (
*Who do we appreciate?*) - 8 - 7 =
**1**. 6 - 5 =**1**.... See a pattern? The difference is 1111, but you almost forgot to make it negative! - The difference is
**-1111**.

**Here's a free worksheet to help you practice SubWhole:**

subwhole.pdf |

**Up Next: ConvFrac%**