Add Within 100 - 1st Grade Math

$78$. Add tens: $40 + 30 = 70$, keep ones: $8$, so $78$.

$97$. Add ones: $0 + 7 = 7$, keep tens: $90$, so $97$.

$70$. Add ones: $2 + 8 = 10$, regroup to get $70$.

$26$. Add ones: $9 + 7 = 16$, regroup to get $26$.

$89$. Add ones: $4 + 5 = 9$, keep tens: $80$, so $89$.

$43$. Add ones: $7 + 6 = 13$, regroup to get $43$.

$78$. Add tens: $10 + 60 = 70$, keep ones: $8$, so $78$.

$65$. Add tens: $50 + 10 = 60$, keep ones: $5$, so $65$.

$65$. Add ones: $8 + 7 = 15$, regroup to get $65$.

$93$. Add tens: $70 + 20 = 90$, keep ones: $3$, so $93$.

$66$. Add tens: $20 + 40 = 60$, keep ones: $6$, so $66$.

$71$. Add tens: $40 + 30 = 70$, keep ones: $1$, so $71$.

$39$. Add ones: $4 + 5 = 9$, keep tens: $30$, so $30 + 9 = 39$.

$76$. Add ones: $7 + 9 = 16$, regroup to get $76$.