Students will see relationships and patterns between numbers 1-120. Use the 1-120 write-on / wipe-off Number Board to count and sequence in different ranges. Use any slider with any window to match it to the corresponding numbers on the Number Board. Students then write the missing numbers on the clear window overlays with a wet or dry-erase marker. Includes 4 double-sided write-on / wipe-off 1-120 number boards (blank grid on reverse), 24 two-sided number sliders with two levels of difficulty, 8 double-sided window overlays (16 designs with 32 ways to practice) and activity guide. Color-coded sliders feature numbers 1-120; 2 to 12 times table; and number relationships on next or prior positions between 1 to 12. Use the blank 120 grid printed on the back of the dry erase Number Boards to create your own missing number activities and more.