Shift ciphers were used by Julius Caesar in Roman times. The key is a number which tells you how many letters you’ll shift the alphabet. These are fairly simple to encode and decode. However, you have to be extra careful when encoding because mistakes can throw off the decoding process. Watch the video to see why it’s important to double check your work!
[am4show have=’p8;p9;p11;p38;p102;p154;’ guest_error=’Guest error message’ user_error=’User error message’ ]
Download Student Worksheet & Exercises
Do you see why it’s important to double check the encoding? This is a simple code, but it’s easy to shift and end up with a jumble when your message is decoded. So always check your cipher with a practice decoding prior to sharing it.
Exercises
Use the key shift number 4 on the letters of alphabet to code or decode the following:
Encode the following statement:
- OUR SCHOOL WAS THE BEST
- I WAS THE BEST IN MATHEMATICS
- I AM THREE FEET TALL
- OUR SCHOOL HAS GOOD TEACHERS
- COME TO MY RESCUE
Decode the following:
- SAWNA HAWRE JCXQZ
- SDWQE OQDAM PAOQE KJXQZ
- LHAWO AYKIA QKZWU
- EWIKJ IUSWU
- ODAEO WCKKZ OEJCA NMXQZ
[/am4show]
Yes I think you’re right, I’ve edited the video and will get it replaced. Thanks for your eagle eye!
your answer key to one is wrong
abcdefghijklmnopqrstuvwxyz
wxyzabcdefghijklmnopqrstuv
this is what i encoded kqnoy dkkhs wopda xaopz this is what the answer key says kpnoy dkkhs woqda xaoqz at the end yours says q mine says p
Whoops! You’re right… thanks for your eagle eye! I’ve updated the video now so it’s correct. 🙂 Great job – keep it up!
My grand daughter caught your mistake. The only thing is, she saw the o was correct, and you just forgot to put the x for the b. She is loving these!
This is so cool! I want to teach this to a few of my friends!