Comparing, ordering and number patterns

Comparing two numbers

To compare two 2-digit numbers, look at the tens first. $43$ and $38$: four tens beats three tens, so $43>38$. Only when the tens are equal do you look at the ones: $56$ and $52$ both have five tens, so the ones decide.

The signs point like a hungry mouth at the bigger number: $43>38$ and $38<43$ say exactly the same thing.

Ordering a list

To put numbers in order, do not compare them all at once. Find the smallest, write it down, cross it off, then find the smallest of what is left. Repeating one easy step beats trying to see the whole list at once.

Patterns

A number pattern has a rule. In $2,4,6,8,\ldots$ the rule is +$2$. In $30,25,20,\ldots$ the rule is $-5$. Always test your rule on two steps before you use it — one step can be a coincidence.