# Lesson: Operations with Signed Numbers - Part I

## Comment on Operations with Signed Numbers - Part I

### I needed this basic as I have

I needed this basic as I have been out of school for a long time

### Just wanted to say that I

Just wanted to say that I appreciate you providing these Reinforcement Activities with each lesson. Even though it's been 18+ years since I've taken high school math, fundamentally I understand these rudimentary elements. It's the way the GRE words their questions is what really throws me off. It's almost like I have to learn to speak and comprehend the "GRE language" before I can really excel at the test. ### That's an astute observation.

That's an astute observation. There are many GRE quantitative questions that seem to test students' reading comprehension skills more than their math skills.

### I have a problem with

When we replace each * with 5, the addition doesn't work.
When we replace each * with 6, the addition works!

My question what i don't understand why doesn't the addition work like is there a rule or something.like 4 + 5 + 5 = 14 but we accepted 4 + 6 + 6 = 16 Why? Sorry, but I'm not quite sure I understand what you're asking. Can you please rephrase your question?

In the meantime, I'll explain a little bit more about what the question is asking just in case this is where you're having difficulties.

In the question, we're adding three 3-digit values to get a 4-digit sum.
We're told 734 + 5*8 + 9*2 = 22*4

The idea here is that each * represents the same digit for all 3 values in the sum.
Note: the * symbol does not represent multiplication.

So, for example, if * = 1, then our sum becomes 734 + 518 + 912 = 2214
Note: 734 + 518 + 912 does not equal 2214, so * = 1 does not make the equation true.

If * = 6, then our sum becomes 734 + 568 + 962 = 2264 (works!)

Does that help?

### Oh as it represents same

Oh as it represents same digit so if we do 5 + 5 + 4 we get 14 not 15 but 6 + 6 + 4 we get 16 as 6 in tens place and *'s have 6 so same digit as added.....oh that's a sneaky one That's right.