Sjmarf@sh.itjust.works to People Twitter@sh.itjust.works · 1 year agoIt looks so wrongsh.itjust.worksexternal-linkmessage-square71fedilinkarrow-up1635arrow-down130
arrow-up1605arrow-down1external-linkIt looks so wrongsh.itjust.worksSjmarf@sh.itjust.works to People Twitter@sh.itjust.works · 1 year agomessage-square71fedilink
minus-squareElvith Ma'for@feddit.orglinkfedilinkarrow-up22·1 year agoThe digit sum of 51 is 6, which is divisible by three. So 51 is also divisible by three. It’s not even hard to see that it’s not prime.
minus-squaresugar_in_your_tea@sh.itjust.workslinkfedilinkarrow-up15·edit-21 year agoYup, my personal prime check is: Even? Ends in 5? Digits sum to 3? If it fails all three and it’s not an “obvious” prime (<20), then it’s prime enough for me.
minus-squareKnock_Knock_Lemmy_In@lemmy.worldlinkfedilinkarrow-up2·1 year agoAlso Ends in 0, but that’s covered by 5 really.
minus-squaresugar_in_your_tea@sh.itjust.workslinkfedilinkarrow-up7·1 year agoIt’s also covered by being even.
The digit sum of 51 is 6, which is divisible by three. So 51 is also divisible by three. It’s not even hard to see that it’s not prime.
Yup, my personal prime check is:
If it fails all three and it’s not an “obvious” prime (<20), then it’s prime enough for me.
Also
Ends in 0,
but that’s covered by 5 really.
It’s also covered by being even.