Puzzle for March 14, 2023  ( )

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Find the 6-digit number ABCDEF by solving the following equations:

eq.1) A = B - F eq.2) C = E - F eq.3) B + D = C + E - D eq.4) C - A = B - D - E eq.5) A + B + F = C + D + E eq.6) D - F = (B ÷ A) + (E ÷ C)

A, B, C, D, E, and F each represent a one-digit non-negative integer.

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Hint #1


Add A, D, and E to both sides of eq.4: C - A + A + D + E = B - D - E + A + D + E which becomes eq.4a) C + D + E = B + A


  

Hint #2


In eq.5, replace C + D + E with B + A (from eq.4a): A + B + F = B + A Subtract A and B from both sides of the above equation: A + B + F - A - B = B + A - A - B which makes F = 0


  

Hint #3


In eq.1, replace F with 0: A = B - 0 which makes A = B


  

Hint #4


In eq.2, replace F with 0: C = E - 0 which makes C = E


  

Hint #5


In eq.6, substitute 0 for F, A for B, and C for E: D - 0 = (A ÷ A) + (C ÷ C) which becomes D = 1 + 1 which makes D = 2


  

Hint #6


Substitute 2 for D, and C for E in eq.3: B + 2 = C + C - 2 which becomes B + 2 = 2×C - 2 Subtract 2 from each side of the equation above: B + 2 - 2 = 2×C - 2 - 2 which makes B = 2×C - 4 and also makes eq.3a) A = B = 2×C - 4


  

Hint #7


Substitute 2 for D, C for E, and 2×C - 4 for B and A (from eq.3a) in eq.4a: C + 2 + C = 2×C - 4 + 2×C - 4 which becomes 2×C + 2 = 4×C - 8 In the above equation, subtract 2×C from both sides, and add 8 to both sides: 2×C + 2 - 2×C + 8 = 4×C - 8 - 2×C + 8 which simplifies to 10 = 2×C Divide both sides by 2: 10 ÷ 2 = 2×C ÷ 2 which makes 5 = C and also makes E = C = 5


  

Solution

Substitute 5 for C in eq.3a: A = B = 2×5 - 4 which becomes A = B = 10 - 4 which makes A = B = 6 and makes ABCDEF = 665250