tolong kak dijawab no 1 dan 2 latihan 4

18= [1] [18]
[2] [9]
[3] [6]

21= [1] [21]
[3] [7]

15= [1] [15]
[3] [5]

40= [1] [40]
[2] [20]
[4] [10]
[5] [8]