Brain Out Level 111
📝 Walkthrough
Overview
The prompt asks you to add one line to make the equation true. Written across the board is 5 + 5 + 5 = 550, which does not balance as it stands. You may draw a single stroke somewhere on the symbols, and the intended move is not to change the result on the right. Turning one of the plus signs into a four digit produces 5 + 545 = 550, which balances exactly. The extra line converts a plus sign into the vertical and horizontal shape of a 4.
- Difficulty: Regular
- Estimated moves: 1
Step-by-Step Solution
- Read the equation on the board: 5 + 5 + 5 = 550. Check the arithmetic as written: the left side adds to fifteen, far below the right side's five hundred fifty.
- Remember the rule: you may add only one line, so a single stroke must alter one symbol into another readable symbol.
- Focus on the second plus sign, the one between the middle 5 and the third 5. This plus sits next to digits that can merge into a three-digit number.
- Draw one stroke across that plus sign to turn it into the digit 4. The added line completes the 4 shape, leaving the middle 5, the new 4, and the third 5 reading as 545.
- Read the modified equation: 5 + 545 = 550. Verify the addition: five plus five hundred forty-five equals five hundred fifty, matching the right side.
- The level recognizes the corrected equation and a green checkmark appears over the altered side. If the check does not appear, confirm the line was added to the second plus sign rather than to a digit or the equals sign.
Strategy & Reasoning
Matchstick-style equation puzzles look for the smallest symbol change that re-balances the sum. Changing a digit with one stroke is hard here, but a plus sign can be reshaped into a 4 by adding one angled or vertical stroke, which frees the surrounding 5s to form 545. That three-digit number then pairs with the remaining 5 to reach 550.
Trying to erase or rewrite the right-side result fails because only one line may be added, and the equation's right side already matches the intended total. Other plus-to-digit placements produce sums that still do not reach 550. Checking the new addition after drawing the stroke confirms the left side reads 545 plus 5, not a malformed sign. The one-line budget makes this reshaping the only solution that balances the equation without altering multiple symbols.
Tips & Common Mistakes
- Add the line to the second plus sign so it becomes a 4 forming 545; do not draw on the equals sign or the 550 result.
- Verify the new left side reads 5 + 545 = 550 before expecting the checkmark.
- Do not attempt to rewrite digits with multiple strokes; the level allows only one added line.