Caught my 5-year-old son counting by twos — “Two, four, six,…”. And I’m positive that it had nothing to do with him singing a memorized, “Two, four, six, eight, who do we appreciate?”
He was counting the fourteen squares on a placemat at dinner. He used his index and middle fingers to pair them up as he counted and you could see him trying to skip the odd numbers as he got passed eight — mouthing the odd numbers and then saying the even ones out loud.
Although I believe there are number facts worth memorizing (like mutiplication tables through 12), we’ve emphasized patterns with our kids.
Ten is an even number, we tell them while holding up both hands, because everyone has a partner. Using our fingers we show them that 1+1 is 2, 2+2 is 4, 3+3 is 6, and 4+4 is 8. Each time we emphasize that 2, 4, 6, & 8 are even because everyone has a partner.
This is foundational because once kids learn they don’t have to count by ones all the time, they can learn to count in groups of twos, threes, fours, fives, etc. This is the beginning of understanding multiplication. In counting by twos, my son is reciting the multiples of two. As he continues doing this he will recognize and “memorize” a rule that all even numbers end in 0, 2, 4, 6, or 8.