This cross-curricular warm-up provides cryptology connections to the Pearl Harbor attack on December 7 of the Mystery Year. Math clues for finding the year require students to evaluate expressions at specific values of their variables to decode a message, operations with decimals, and reasoning skills.Your PDF download includes:2-page digital version with horizontal layout, prepped for Easel1-page printable version3 pages of Teacher Notes including step-by-step Solutions, Extensions, and a varie