Ruel has four books of 10 stamps and six books of 15 stamps. How many stamps does Ruel have?
Ruel has a total of 4 x 10 = <<4*10=40>>40 stamps from the four books.
He also has 6 x 15 = <<6*15=90>>90 stamps from the six books.
Therefore, he has a total of 40 + 90 = <<40+90=130>>130 stamps.
#### 130