Maths with DST

We made a kiss (cross) out of 5 multi-link cubes. Then we talked about how to make the kiss grow and predicted how many cubes we needed to add to make the next kiss. In pairs, with our DST friends, we did some building and working out to find out the number of cubes needed for the 2nd, 3rd, 4th....kisses. Every one noticed an adding pattern. Each time we added 4 cubes to make the next kiss. Some of us worked out how many cubes would be needed for the 100th kiss. We didn't build it - there wasn't time!! We knew that we would need 401 cubes. This is what we did 4 x 100 + 1 =401. We multiplied by 4 because each kiss has 4 branches. The 100 is in the sum because we were calculating the result for the 100th kiss and +1 because there is always 1 cube in the middle to hold the branches together. Here are some pictures of us working.