Build number sense through puzzles, games, and logical reasoning about how numbers behave.
In a row of numbers, a number that is bigger than all its neighbours can be picked out just by comparing it to the numbers directly next to it — no need to compare it to every number in the row.
In the row 5, 9, 3, 8, 2, which numbers are bigger than both of their neighbours?
9 (bigger than 5 and 3) and 8 (bigger than 3 and 2)
In the row 4, 7, 2, 9, 1, which number is bigger than both neighbours and also the biggest in the whole row?
9
Many number puzzles can be solved by careful reasoning rather than guesswork — working out what must be true step by step.
I am thinking of a number. If you double it and add 3, you get 11. What is the number?
4 (since 4 × 2 + 3 = 11)
A 2-digit number has digits that add up to 9, and the tens digit is twice the units digit. What is the number?
63 (6 + 3 = 9, and 6 is twice 3)
1. In the row 3, 6, 2, 8, 1, which numbers are bigger than both neighbours?
2. I am thinking of a number. If you triple it and subtract 2, you get 13. What is the number?
3. A 2-digit number has digits that add up to 10, and the units digit is 4 more than the tens digit. What is the number?
4. What is the largest 3-digit number you can make using the digits 5, 2, and 8 exactly once each?
5. What is the smallest 3-digit number you can make using the digits 4, 0, and 7 exactly once each (not starting with 0)?