Brain Teasers
Counting on Fingers
A mathematician walks in on his daughter counting on her fingers. He has no problem with this, but finds it odd that after counting to five (thumb to pinky finger), she doubles back and counts her ring finger as six, middle finger as seven, etc.
When the girl gets to twenty, on her ring finger, her father asks her what she is doing.
"I want to see what finger the number 1972 lands on," the young girl replies. The father chuckles, does some quick arithmetic and tells the girl the finger on which she will land. How does he do it, and on what finger will his daughter finish?
When the girl gets to twenty, on her ring finger, her father asks her what she is doing.
"I want to see what finger the number 1972 lands on," the young girl replies. The father chuckles, does some quick arithmetic and tells the girl the finger on which she will land. How does he do it, and on what finger will his daughter finish?
Answer
The girl will land on her ring finger.The number of the thumb minus one is always divisible by eight.
Divide with remainder: 1972/8=246R4
Count the thumb as one. The ring finger is four.
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