### Biscuit Decorations

Andrew decorated 20 biscuits to take to a party. He lined them up and put icing on every second biscuit and different decorations on other biscuits. How many biscuits weren't decorated?

### Writing Digits

Lee was writing all the counting numbers from 1 to 20. She stopped for a rest after writing seventeen digits. What was the last number she wrote?

### Next Domino

Which comes next in each pattern of dominoes?

If you put three beads onto a tens/units abacus you could make the numbers $3$, $30$, $12$ or $21$.