Vertical Addition: Addition of 2-digit and 2-digit numbers with the regrouping of tens and ones

$\begin{aligned} &15 \\ +& \\ &56 \\ &\underline{\phantom{776}} & \\ \end{aligned}$

71

$\begin{aligned} &65 \\ +& \\ &18 \\ &\underline{\phantom{776}} & \\ \end{aligned}$

83

$\begin{aligned} &37 \\ +& \\ &46 \\ &\underline{\phantom{776}} & \\ \end{aligned}$

83

$\begin{aligned} &47 \\ +& \\ &25 \\ &\underline{\phantom{776}} & \\ \end{aligned}$

72

$\begin{aligned} &23 \\ +& \\ &59 \\ &\underline{\phantom{776}} & \\ \end{aligned}$

82

$\begin{aligned} &52 \\ +& \\ &39 \\ &\underline{\phantom{776}} & \\ \end{aligned}$

91

$\begin{aligned} &73\\ +& \\ &18 \\ &\underline{\phantom{776}} & \\ \end{aligned}$

91