We are interested in the fact family of $1$1,$8$8 and $9$9.
$+$+ | $=$= | |||
$8$8 | $+$+ | $1$1 | $=$= | $9$9 |
What is $1+8$1+8?
What is $9-8$9−8?
What is $9-1$9−1?
We are interested in the fact family of $4$4,$6$6 and $10$10.
We are interested in the fact family of $5$5,$5$5 and $10$10.
We are interested in the fact family of $2$2, $4$4 and $6$6: