Sjmarf@sh.itjust.works to People Twitter@sh.itjust.works · 8 天前It looks so wrongsh.itjust.worksimagemessage-square72fedilinkarrow-up1630arrow-down130
arrow-up1600arrow-down1imageIt looks so wrongsh.itjust.worksSjmarf@sh.itjust.works to People Twitter@sh.itjust.works · 8 天前message-square72fedilink
minus-squareElvith Ma'for@feddit.orglinkfedilinkarrow-up22·8 天前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.
minus-squaresugar_in_your_tea@sh.itjust.workslinkfedilinkarrow-up15·edit-27 天前Yup, 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-up2·7 天前Also Ends in 0, but that’s covered by 5 really.
minus-squaresugar_in_your_tea@sh.itjust.workslinkfedilinkarrow-up7·7 天前It’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.