Sean (aged 7) coding number sentences

(* Simple number sentences
25 + 13
= 20 + 5 + 10 + 3
= 30 + 8
= 38
*)

let tens number = (number / 10) * 10

let ones number = number % 10

let split number = (tens number, ones number)

let sentence a b =
    let a10, a1 = split a
    let b10, b1 = split b
    printfn "= %d + %d + %d + %d" a10 a1 b10 b1
    printfn "= %d + %d" (a10+b10) (a1+b1)
    printfn "= %d" (a+b)

sentence 25 13