Brain Test 5 Level 17

Overview

"Complete the pattern." The board presents three separate number puzzles in sequence, each asking you to fill a blank from a short sequence or a two-by-two grid. The final frames show three 2-by-2 grids where the top-row numbers are divided by three to produce the bottom-row numbers, with an underlined answer cell and a 0-to-9 number pad for entry.

• Difficulty: Hard
• Estimated moves: 3

Step-by-Step Solution

1. First pattern: read the repeating sequence 1, 2, 3, 4 as a cycle that loops back to the start. Fill the blanks in order with the next cycle members, which are 2 and then 3, keeping the original four-digit order intact.
2. Second pattern: look at how each four-digit group rotates to the right. The shown groups are 4765, then 5476, then 6547; in each step the last digit moves to the front while the others shift one place right. Applying the same rotation to 6547 gives the next group 7654.
3. Third pattern: examine the two-by-two grids, such as the first with 6 and 9 on top and 2 and 3 on the bottom, and the second with 3 and 6 on top and 1 and 2 on the bottom. Notice each bottom number equals the top number divided by three: 6 ÷ 3 = 2, 9 ÷ 3 = 3, and 3 ÷ 3 = 1, 6 ÷ 3 = 2.
4. Apply that division to the third grid: 9 ÷ 3 = 3 on the left, and 12 ÷ 3 = 4 on the right. The underlined bottom-right answer is 4, entered from the number pad.
5. After the three blanks match their patterns, the green checkmark appears over the grid set and the level completes.

Strategy & Reasoning

Each panel uses a different arithmetic rule, so the first job is to identify which rule a panel follows before touching the pad. The first panel is a pure repetition loop with no operation between terms, the second is a positional rotation rather than a sum or product, and the third is a fixed division relationship between rows. Mixing these rules up — for example, subtracting the second panel's digits, or multiplying the third panel's rows — produces answers that do not match the shown examples.
The two-by-two grids are the most reliable check because their internal ratios are explicit. Comparing the first two grids proves the divide-by-three rule before you trust it on the third: every top number is exactly three times the bottom number below it. Once that relationship is confirmed, the missing value follows directly from division rather than guesswork. The rotation panel, by contrast, must be traced digit by digit, watching which digit jumps to the front each time; counting from the left instead of tracking the moving digit usually scrambles the group.

Tips & Common Mistakes

• Solve one panel at a time and name its rule first; do not apply the division idea to the repeating or rotation sequences.
• In the rotation panel, track the digit that moves to the front rather than reading the group left to right as a normal number.
• Double-check the divide-by-three grids against the completed examples before entering 4; a top number that is not a multiple of three signals you have misread the row.