hard Set 81 Form Exercise

Number Chain: 12 → -8 → -2 → -1 → x2 → +10 → ?

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Answer: 12

SubType
number-chain
Start
12
Steps
  • {"op":"-","operand":8}
  • {"op":"-","operand":2}
  • {"op":"-","operand":1}
  • {"op":"x","operand":2}
  • {"op":"+","operand":10}
Difficulty
hard

Number Chain: 7 → +2 → -2 → -2 → x5 → x3 → ?

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Answer: 75

SubType
number-chain
Start
7
Steps
  • {"op":"+","operand":2}
  • {"op":"-","operand":2}
  • {"op":"-","operand":2}
  • {"op":"x","operand":5}
  • {"op":"x","operand":3}
Difficulty
hard

Number Chain: 2 → -1 → +3 → x5 → -13 → -1 → ?

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Answer: 6

SubType
number-chain
Start
2
Steps
  • {"op":"-","operand":1}
  • {"op":"+","operand":3}
  • {"op":"x","operand":5}
  • {"op":"-","operand":13}
  • {"op":"-","operand":1}
Difficulty
hard

Number Chain: 6 → x5 → +10 → x4 → x2 → x5 → ?

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Answer: 1600

SubType
number-chain
Start
6
Steps
  • {"op":"x","operand":5}
  • {"op":"+","operand":10}
  • {"op":"x","operand":4}
  • {"op":"x","operand":2}
  • {"op":"x","operand":5}
Difficulty
hard

Number Chain: 11 → x2 → +12 → -25 → +6 → +12 → ?

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Answer: 27

SubType
number-chain
Start
11
Steps
  • {"op":"x","operand":2}
  • {"op":"+","operand":12}
  • {"op":"-","operand":25}
  • {"op":"+","operand":6}
  • {"op":"+","operand":12}
Difficulty
hard

Number Chain: 4 → x2 → -4 → -3 → +1 → +3 → ?

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Answer: 5

SubType
number-chain
Start
4
Steps
  • {"op":"x","operand":2}
  • {"op":"-","operand":4}
  • {"op":"-","operand":3}
  • {"op":"+","operand":1}
  • {"op":"+","operand":3}
Difficulty
hard

Number Chain: 11 → +5 → x5 → +7 → x2 → +6 → ?

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Answer: 180

SubType
number-chain
Start
11
Steps
  • {"op":"+","operand":5}
  • {"op":"x","operand":5}
  • {"op":"+","operand":7}
  • {"op":"x","operand":2}
  • {"op":"+","operand":6}
Difficulty
hard

Number Chain: 1 → +10 → +11 → x2 → +3 → +5 → ?

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Answer: 52

SubType
number-chain
Start
1
Steps
  • {"op":"+","operand":10}
  • {"op":"+","operand":11}
  • {"op":"x","operand":2}
  • {"op":"+","operand":3}
  • {"op":"+","operand":5}
Difficulty
hard