Addition and Subtraction Within 30 Mystery Pictures

Children add and subtract with numbers up to 30 and cross ten along the way: 17 + 6, 26 − 8, 19 + 5, 30 − 12. Since every answer has to match a row on the grid, results never go past the height of the picture, and the bigger numbers appear mostly as the starting number in a subtraction, such as 27 − 9 or 24 − 7. That makes this topic particularly strong on subtracting across a ten from the twenties, which many children find harder than adding.

The layout is the coordinates format again: rows are numbered down the side, columns lettered across the top, and problems grouped under color names. Tall grids fit best on the two-page layout, where the squares stay big enough to color neatly. Teachers often use it as a second-grade review at the start of the year, or as a stretch for first graders who have mastered 20. Choose five variants when children work side by side.

Encourage a jump back to the nearest ten when subtracting: for 26 − 8, first 26 − 6 = 20, then 20 − 2 = 18. Writing that middle step in the margin is fine, and it makes any error easy to trace when you compare with the answer key.