Math Functions, Powers and Ratios

Calto is not only for money. The same note handles the small math you would otherwise open a spreadsheet for.

Percent change

before = 1250
after = 1600
change = after - before        → 350
change / before * 100          → 28

Compound growth

principal = 10k
rate = 4%
years = 5
principal * (1 + rate)^years   → 12,166.53

10k is 10,000. 4% alone is 0.04. ^ is the exponent.

Rounding

round(12.5)                    → 13
floor(12.9)                    → 12
ceil(12.1)                     → 13
abs(-8)                        → 8

Roots, logs, trig

sqrt(2)                        → 1.41
log(1000)                      → 3
ln(exp(2))                     → 2
sin(0)                         → 0

log is base 10; ln is natural. Trig functions take radians; convert with 45deg in rad.

Modulo: every nth item

items = 47
box = 6
items mod box              → 5

Five items are left over after filling 7 boxes.

Scaling a recipe

A proportion with ? in the unknown slot.

4 : 250 = 6 : ?                → 375

Four servings need 250 g; six servings need 375 g.

Scale models

1 : 87 = ? : 2000              → 22.99

A 2,000 cm real object is about 23 cm at 1:87.