Does anyone know how to calculate a Mod b in Casio fx-991ES Calculator. Thanks
Modulo Calculator Modulo is frequently expressed as a mod b; however, in some cases, it can be expressed as a % b. On calculators, modulo is often calculated using the mod() function: mod(a, b) = r.
This calculator does not have any modulo function. However there is quite simple way how to compute modulo using display mode ab/c
(instead of traditional d/c
).
How to switch display mode to ab/c
:
ab/c
(number 1).Now do your calculation (in comp mode), like 50 / 3
and you will see 16 2/3
, thus, mod is 2
. Or try 54 / 7
which is 7 5/7
(mod is 5
). If you don't see any fraction then the mod is 0
like 50 / 5 = 10
(mod is 0
).
The remainder fraction is shown in reduced form, so 60 / 8
will result in 7 1/2
. Remainder is 1/2
which is 4/8
so mod is 4
.
EDIT: As @lawal correctly pointed out, this method is a little bit tricky for negative numbers because the sign of the result would be negative.
For example -121 / 26 = -4 17/26
, thus, mod is -17
which is +9
in mod 26. Alternatively you can add the modulo base to the computation for negative numbers: -121 / 26 + 26 = 21 9/26
(mod is 9
).
EDIT2: As @simpatico pointed out, this method will not work for numbers that are out of calculator's precision. If you want to compute say 200^5 mod 391
then some tricks from algebra are needed. For example, using rule (A * B) mod C = ((A mod C) * B) mod C
we can write:
200^5 mod 391 = (200^3 * 200^2) mod 391 = ((200^3 mod 391) * 200^2) mod 391 = 98
As far as I know, that calculator does not offer mod functions. You can however computer it by hand in a fairly straightforward manner. Ex.
(1)50 mod 3
(2)50/3 = 16.66666667
(3)16.66666667 - 16 = 0.66666667
(4)0.66666667 * 3 = 2
Therefore 50 mod 3 = 2
Things to Note: On line 3, we got the "minus 16" by looking at the result from line (2) and ignoring everything after the decimal. The 3 in line (4) is the same 3 from line (1).
Hope that Helped.
Edit As a result of some trials you may get x.99991 which you will then round up to the number x+1.
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