Disclaimer: I don't own Numb3rs or anything associated with it. This is for entertainment only.

Author's note: I seem to be addicted to stories about Don and Charlie as children, so this is yet another offering. It's really just fluff, but I hope it's still enjoyable.

The title is from the song Rocketman by Elton John

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When Don got home from baseball practice Charlie didn't come to the door to meet him. This was a shock because Charlie was always the first to pounce on Don as he walked in the door. But there were times when Charlie got so absorbed in whatever he was doing that he lost track of time, and pretty much everything else that wasn't his 'work'. Don thought it was funny to think of an eleven year old with work to do. But then the way his tutors pushed him, you'd think Charlie had to solve the mysteries of the universe by the time he was thirteen.

Don shook his head. How different his and Charlie's worlds were going to be. How different they already were. Charlie with his math. Constantly stuck in his head. His own little world, his bubble. Don out in the real world. More concerned with physical things, things he could see and touch. Things that had as little to do with his brain as possible. Like Pam. He really should call her. She had such great...

"Don."

Margaret was standing in front of him with an irritated look on her face. "You're getting mud all over my clean floor."

Don looked down. He was standing in an ever growing pile of dirt and grass. "Sorry." He made to walk upstairs but his mother stopped him.

"Where do you think you're going?"

Don gestured weakly at the stairs but he knew it was the wrong answer.

"Wrong. You're going round the back to take off your dirty clothes and shoes, and then you can come in."

"Mum..." Don knew there was no point in arguing, but he couldn't help but feel embarrassed at having to take all his clothes off in the backyard. What if the neighbours saw?

Margaret didn't say anything but by the look on her face Don could tell that she didn't give a damn about her son's dignity. Grudgingly Don turned and walked back out of the house.

As he reached the garage a sound that had become extremely familiar reached Don's ears. The click, click, click of chalk on a blackboard. Obviously Charlie was working on one of his math problems. Don hesitated, not knowing if he wanted to distract Charlie. But then he remembered that he had to strip in front of the neighbours and decided he would like to postpone that as long as possible. So, venturing into the garage, Don entered Charlie's world.

Charlie's world consisted mainly of blackboards. Dozens of them. Covering every wall. A sea of black canvases, most covered with an almost illegible white scrawl. Charlie's writing. Writing in a language that made no sense to Don, or most other people.

When the garage had first been set up for Charlie, Don had felt intimidated by it. For weeks he refused to go in, saying the whole thing was too creepy. It had been his own feelings of inferiority at Charlie's 'gift' that kept him away. After a while he came to realise that he didn't need Charlie's brains. He was quite happy with his own life. He did okay at school, had lots of friends, was excellent at baseball, and that was all he needed. Anyway he had seen first hand how Charlie's gift could easily turn into a curse.

Don spied Charlie, crouching in front of a blackboard in the corner. He was hunched over so all Don could see was his back and his mop of black curls. Don chuckled, he really needed a haircut. Sensing his older brother's presence, Charlie turned. Looking at Don with wide brown eyes, his startled face slowly broke into a smile.

"Hi Don." He even waved.

"Hey buddy. Whatcha doing?"

Charlie contemplated Don for a moment before turning back to his work. He quickly finished off the line he was writing and jumped up, walking backwards he finally came to stand beside Don.

"I'm working on something."

Don resisted the urge to say 'duh', knowing that Charlie was sometimes hesitant to explain his work. He knew that people got bored of it, especially when they didn't understand. What Charlie didn't realise was that people usually didn't understand any of it.

Punching Charlie gently in the arm, Don let his baby brother know that he was in the talking mood. "What is it?"

Don just assumed the work was something Charlie's tutors had set for him, and so was surprised when Charlie answered.

"I'm building a rocket to the moon."

Don snorted with laughter, which he quickly tried to change into a cough but ended up almost choking himself.

"The moon, huh?"

Charlie's eyes didn't leave the work. "Yeah."

Don couldn't imagine where the idea of going to the moon had come from. Charlie didn't usually go off on tangents. Don was the one who almost drowned the pet mouse trying to teach it to swim. Don was the one who broke his arm when he jumped off the roof trying to fly. Don was the one who put the firecracker in the letterbox just to see what would happen.

A horrible thought hit Don. Charlie wasn't going to try to send himself to space, was he? Don imagined the whole thing going up in a blaze of explosives and flammable material.

"Charlie, you don't mean you're going to the moon, right?"

Charlie gave Don a strange look. "Of course not. Only NASA can do that. I'm just going to build a little rocket and then send it into space."

Don sighed inwardly, but the idea of Charlie getting hurt stuck in his mind. He'd still have to use some kind of explosives, some kind of fuel.

"What exactly do you know about building rockets?"

At that Charlie came alive. "Oh I''ve worked it all out, see." He pointed to one of the blackboards to the right. Don nodded even though he had no idea what he was looking at. "The math's almost done. I just have to fix a few things and that'll be it."

Don realised Charlie was missing something. "But where's your rocket?"

Again Charlie gave Don a strange look, as if he had just said the most obviously stupid thing in the world. When he spoke he did so very slowly.

"The math is the hard part. Anyone can build a rocket."

Don laughed. "Okay then, well good luck." Turning around he went to leave, but then stopped, suddenly remembering something. "Don't play with fire or anything like that. Get dad or I to help, okay?"

Charlie waved absently, already absorbed back in his work.

Don didn't tell his parents about Charlie's little project. He was afraid that they would stop him. Although Don was doubtful he would succeed, Charlie needed this project. Needed to start acting a little more like an eleven year old boy and less like a fifty year old professor.

Charlie didn't come in for dinner, Margaret ended up taking his plate out to the garage, and when Don went up to his room at nine Charlie was still working.

Falling asleep somewhere around ten, Don woke with a start two hours later. For some reason all he could think about was Charlie, and had the irrational idea that he was still out working even thought it was past twelve. Knowing that his parents would have put Charlie to bed hours ago, Don still couldn't push the idea from his head. Walking quietly down the hall, Don resolved to check in on Charlie quickly and then go back to bed.

Pushing Charlie's door open, Don was shocked to find his bed empty. Fighting the panic that fluttered in his stomach, Don forced himself to calm down. Charlie was probably just getting a glass of water, or going to the bathroom. Still Don knew that he wouldn't be able to sleep until he found his little brother.

Charlie wasn't in the bathroom, or the kitchen. He wasn't in the lounge room, or in his parent's room. Only one place remained and Don was pretty sure that's where he would be. Walking towards the garage Don could see the light inside was on. He could even hear sounds coming from within the room, but it wasn't the usual clicking of chalk. It sounded like someone was talking.

Walking slowly into the room Don could see Charlie, sitting in the middle of the room surrounded by an assortment of things. From what Don could make out they included sticky tape, paper, plastic cups, string and some batteries. Charlie was sitting in the middle of this sea, bent over and mumbling to himself. Don couldn't hear what he was saying but by the tone of his voice he sounded distressed. Worried that Charlie was having another one of his panic attacks, Don knocked on the wall, alerting Charlie to his presence.

Charlie's whole body jumped in fright, and he spun around to look at Don before quickly turning away again. Although Charlie tried to hide it, Don could see he was wiping at his face. Wiping away tears. Walking over to his younger brother, Don dropped to one knee.

"Hey buddy, what's wrong?"

Charlie sniffed, trying to hide his distress. Placing a hand on Charlie's head, he turned his younger brother's face to him. Charlie's eyes were red with tears and possibly exhaustion.

"It's my rocket."

Don looked at the paraphernalia covering the floor. Charlie wasn't really trying to build a rocket out of this stuff?

"Oh, Charlie."

Don could have laughed. For all his genius, his eleven year old brother didn't know that you couldn't make a rocket out of paper and sticky tape, and batteries.

Wiping his nose on his sleeve, Charlie tried to rally himself. "I thought it would be easy. I did all the math." He waved towards the blackboards. "It should have been easy."

Don did laugh this time. He reached out and hugged his little brother close. "Charlie, what are we going to do with you?"

Charlie didn't see the humour that Don saw in the situation. "It's not funny, Don."

This only made Don laugh harder as he helped his brother off the floor.

"You're right, it's not. Mum's going to kill you when she finds out you've been using her best scissors."

Don walked Charlie all the way to his room. The younger boy still seemed distracted as Don tucked him into bed. "What about the mess?"

Don ruffled Charlie's hair. "Don't worry about it. I'll clean it up tomorrow morning." He could tell there was something else Charlie wanted to ask him, so he waited.

"What about my rocket?"

Don smiled, half expecting the question. "Tomorrow, we'll work on the rocket together. Now go to sleep."

As if on command, Charlie closed his eyes. Don walked quietly out of the room, but left the door half open.

Finally making it into his own bed, Don collapsed against the pillow. He was still smiling to himself. The situation was so typical of Charlie. Thinking that as long as he had the math, everything else would be easy. That math was the answer to everything. Of course Don knew that wasn't true.

Yet some part of him was glad. Happy in the knowledge that he still had some relevance in Charlie's life. And years from now, when someone asked about his little brother's rocket making skills, Charlie could utter those wonderful words.

"My brother taught me."

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A/N: Despite the lovely reviews, I'm having trouble with my other story Grief. I've also just realised I got a lot more reviews than I thought, obviously the alerts weren't working. So thanks to all of you who reviewed. I'm really sorry about the long wait but I promise something in the next week.