Add 2-digit numbers by making tens

**Complete to solve $63 + 7$.** $\phantom{=}63+7$ $=(60+$ [[☃ input-number 1]]$)+ 7$ $=60 + ($[[☃ input-number 2]] $+ 7)$ $=60 + $ [[☃ input-number 3]] $=$ [[☃ input-number 4]]