# Make an equation from expression "1 4 9 100" [closed]

Fill the gaps of the expression $$1$$ $$4$$ $$9$$ $$100$$ with mathematical operations $$+,-,*,/$$, physical units and an $$=$$ sign, such that a correct equation is created.
Example: expression $$1$$ $$100$$ $$100$$ $$9$$ -> $$1 \text{m} = 100 \text{mm} + 100 \cdot 9 \text{mm}$$

• Would something like 1 feet = 2 * 2 * 3 inches for 1 2 2 3 be allowed? Jul 1, 2021 at 18:53
• yes, this is a valid solution for 1 2 2 3 Jul 1, 2021 at 18:56
• what about something like 4 ft * 6 in = 2 ft^2 * 1 for 4 6 2 1? where ft^2 is the same as sqft which is square feet? Jul 1, 2021 at 19:05
• @rhavelka, yes, this is a valid solution as well. Jul 1, 2021 at 21:11
• @IsaacRoanSison I do not think that the approximate symbol would work since the question strictly states an "=" sign. Jul 2, 2021 at 0:20

Hmm, let's see.

1 hour = 4 * 9 * 100 seconds

A few more possibilities:

With pints and fluid ounces
1x4 pt = 9 pt - 100 fl oz

With feet and inches
1 ft - 4 in = 9 ft - 100 in

With angles
1° = 4x9x100"

There are some non-standard "journalism units" like "Olympic swimming pool" for volume, "Texas" for area, or "Library of Congress" for amount of data. One of these, recognized by the units program, is "football field = 100 yards".
If we allow these, then 1 football field = 4 * 9 inches * 100

Alternatively, if you permit SI prefixes on very non-SI units, then 1 * 4 * 9 inches = 100 centiyards :)

if base number is a valid unit then 1 * 4 * 9 (decimal)= 100 (Senary, heximal, or seximal, base-6)