How to solve for X math tutorial: introducing "Math with Margo"

iD Tech in action

Solving for X...One of the most fundamental algebra concepts.

It’s also one of the most confusing!

Never fear, our very own iD Tech math superhero, Margo, is here to help. 

Follow along in this easy tutorial and solving for x will be a snap! Read Margo’s notes and highlights for extra tips and tricks. (you’ll be able to check your work as you go.) 

Meet Margo, Math Expert and Operations Manager at iD Tech 

Hi there! My name is Margo Berry, and I was a middle school and high school math teacher for five years. I have an expertise in developing Common Core aligned math curriculum, a Master's Degree in Secondary Math Education, and a passion for making math engaging for kids.

Math is all around us! I like to find ways to provide opportunities for my students to interact with math and see it relate to the real world.

Solve for X Math Tutorial

Solving Two Step Equation Word Problems 

Dan bought eight new baseball trading cards to add to his collection. The next day, his dog ate half of his collection. There are now only thirty eight cards left. How many cards did Dan start with?

Step One: Highlight important parts of the text

Go through the problem and identify the important pieces. These valuable details usually include all numbers and any indication that something is being added, subtracted, divided, or multiplied. 

Step Two: Define your variable(s) or unknowns

The unknown, or what we are trying to solve for is C, or the number of cards Dan started with. 

Step Three: Write your equation(s) by breaking down the text of the problem

Next, begin writing the equation by breaking down the important pieces of the problem.

First, Dan bought eight new cards, so we add C+8. 

(Here is more on converting word problems into equations.)

Next, because Dan's dog ate half of the collection, we divide everything by 2. 

Last, we know that Dan ends up with 38 cards in the end, so we set it equal to 38.

Step Four: Solve your equation!

Now, we are ready to solve! To get C by itself, we must perform inverse operations. In this case, we are dividing C+8 by 2, so we must multiply as the inverse. And then, whatever we do to one side of the equation we must do to the other side of the equation.

After multiplying both sides by 2, we are left with C+8 = 76...meaning we are very close to finding C on its own!

From there, we need to subtract 8 from both sides, ultimately leaving us with our pre-checked answer of C=68! 

Step Five: Check your work

To check our work, take the answer of 68 and go through the different operations as described by the important pieces of the word problem. 

68 original baseball cards (our answer) + 8 new baseball cards Dan bought = 76 total cards. We know Dan's dog ate half of the collection, so 76 divided by 2 = 38...which is the exact amount of cards the word problem told us Dan was left with!

Step Six: State your final answer

After finding C and checking the work to get there, state the final answer in relation to the main question. 

Congratulations! You did it! For more math resources and fun, check out these: 

For support, extra help, and challenges in math, iD Tech offers live online math tutoring in algebra, pre-calculus, geometry and more! 

Options include:

A photo of Virginia

Virginia started with iD Tech at the University of Denver in 2015 and has loved every minute since then! A former teacher by trade, she has a master's in education and loves working to embolden the next generation through STEM. Outside the office, you can usually find her reading a good book, struggling on a yoga mat, or exploring the Rocky Mountains. 

Featured Posts



About iD Tech

iD Tech is the #1 tech camp on the planet, and world leader in youth STEM education, with programs held online and at 75+ global locations offering 50+ innovative tech courses: 

Coding camps
Video game camps
Robotics classes & camps
Creative arts classes & camps
All STEM camps

We've bet our reputation on recruiting the top instructors in the country. Our small classes ensure customized learning, leading to "a-ha moments" and awesome outcomes. Programs include:

On-Campus Programs

Online Tutoring

All Coding Courses