```calc
grade(U) :=
  "OK" if U <= 1
  "fails" otherwise
grade(0.8) = ?
grade(1.2) = ?
```

```calc
fib(n) :=
  a <- 0
  b <- 1
  for k in 1..n
    t <- a + b
    a <- b
    b <- t
  a
fib(10) = ?
```

```calc
peak(v) :=
  k <- 0
  for j in 0..last(v)
    k <- j if v[j] > v[k]
  k
peak([3; 9; 4]) = ?
```

```calc
halvings(x) :=
  n <- 0
  while x > 1
    x <- x/2
    n <- n + 1
  n
halvings(1000) = ?
```