The Weekend Edition Sunday puzzle for this week is
Challenge for February 18: The object of this challenge is to develop nine different mathematical expressions that equal eight. You must use the digits 2, 7 and one other. And that other digit must be a one in the first expression, two in the next expression and so on, up to nine. You can use a digit once and only once in each expression.
You may use the four arithmetic symbols: plus, minus, times and divided by, as well as exponents and decimal points. You may use parenthesis as you need them. For example: Using the digits 2, 7 and 1 you can make the expressions 2+7-1= 8.
This week's Challenge is from Robert Waynewright in New Rochelle, N.Y.
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I'm currently stuck on 2,5,7, and 2,7,7.
Me too. When I went looking for blog comments, I kind of figured that this is what I'd find. The others are relatively easy; there is some complexity in these last too.
ReplyDeleteThink about dividing decimals.
ReplyDelete7/.7 - 2
ReplyDelete.2*5 + 7
ReplyDeleteHa, talk of being stuck in a groove.
ReplyDeleteAnyway, the full set of answers is somewhere else on the site.
somewhere else on this site??? im gettin killed on a couple of these!
ReplyDeleteI'm stuck on 2,7,8. Any hints?
ReplyDelete2,7,8 - use decimals
ReplyDeleteI have solutions for 0,2,7 (7+2**0) and 2,7,10 (2**(10-7)) but can't get 2,7,8. Any ideas?
ReplyDeleteI'm pretty sure the question asks for numbers from 1-9, 0 not included. DOES ANYBODY KNOW 2,7,8???
ReplyDelete2,7,8 is a lot simpler than most of you imagine. It's simply 7.2 + .8, or 7.8 + .2.
ReplyDeleteI'm stuck on 4 and 7!!!
ReplyDelete6...?
ReplyDeleteOK, I had them under "Excitement of Discovery", but here they are, including 0 (0 is not part of the NPR set).
ReplyDelete2^0 + 7
2 + 7 - 1
2/2 + 7
(7 - 3) * 2
2^(7-4)
.5 * 2 + 7
2*7 - 6
7/.7 - 2
7.2 + .8
72/9
Thanks. I have [(7+9)/2] for number 9 - I'm not sure how the 'digit' rule is to be interpretted. For 8 I have [7+(.2+.8)].
ReplyDelete