AR23 - Subtraction with numbers and quantities from 0–10

This puzzle has 20 puzzle pieces, 10 pieces with simple subtraction problems with numbers from 1 - 10 and 10 pieces with the answers. On the frame above the pieces there are funny dogs heads in quantities that symbolize the calculations. There is a cross above some of the heads, the number of heads with crosses should be subtracted from the total number. First, the pieces with the calculations are to be placed under the symbols and then place the pieces with answers. Each piece only fits in its proper place. Children can work at their own pace, try and fail, while learning. Every time a piece falls into place it gives a feeling of mastery, joy and desire to continue playing and learning.