Joelyn and Sharon had an equal number of stickers. After Sharon gave 1,255 stickers to Joelyn, Joelyn had twice as many stickers as Sharon. How many stickers did each of them have at first? explain it to a 4th grader.

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Let's solve this sticker mystery step by step! We start with Joelyn and Sharon having the exact same number of stickers. Think of them as two equal piles of stickers. This is our starting point before anything changes. Now comes the big change! Sharon gives 1,255 stickers to Joelyn. This is like moving stickers from one pile to another. Sharon's pile gets smaller by exactly 1,255 stickers, while Joelyn's pile gets bigger by the same amount. This transfer creates a big difference between their piles. Here's the key insight! When Sharon gives away 1,255 stickers, she loses that amount. When Joelyn receives those same 1,255 stickers, she gains that amount. The total change in the difference between their piles is 1,255 plus 1,255, which equals 2,510 stickers. This total difference of 2,510 is very important for solving our mystery! Now we use the important clue! After the transfer, Joelyn has twice as many stickers as Sharon. This means if Sharon has some amount, Joelyn has exactly double that amount. The difference between twice an amount and the original amount equals the original amount itself! Since we know the difference is 2,510 stickers, Sharon must currently have 2,510 stickers, and Joelyn has 5,020 stickers. Now for the final step! Sharon currently has 2,510 stickers, but she gave away 1,255 stickers earlier. To find how many she had originally, we add back what she gave away: 2,510 plus 1,255 equals 3,765. Since both girls started with equal amounts, each of them had 3,765 stickers at first! We can check our answer: Sharon went from 3,765 to 2,510, and Joelyn went from 3,765 to 5,020, which is exactly twice Sharon's amount. Mystery solved!