1+9=? 2+9=? 3+9=? . . . A law of adding 9 to a number (the previous number minus 1 is a single digit)

1+8=? ... a number plus 8 (the previous number minus 2 is a single digit)

1+7=? ... a number plus 7 (the previous number minus 3 is a single digit)

. . . By analogy

Simple application problem: For example, Xiaoming has an apple and Xiaohong has five. How many people are there?

Pure hand tour, for reference only.