## Understand the problem

## Start with hints

##### Source of the problem

C.M.I (Chennai mathematical institute ) U.G- 2019 entrance

##### Topic

### General concepts + Number theory

##### Difficulty Level

DO you know how to start working backward

working backward means that when you press A is makes -1 from the result and pressing B you can divide 2

strategies are like this , divide the no. as many step you can , when the result it not divisible by 2 just -1

\(260\rightarrow130\rightarrow65\rightarrow64\rightarrow32\rightarrow16\rightarrow8\rightarrow4\rightarrow2\rightarrow1\)

## Connected Program at Cheenta

# I.S.I. & C.M.I. Entrance Program

Indian Statistical Institute and Chennai Mathematical Institute offer challenging bachelor’s program for gifted students. These courses are B.Stat and B.Math program in I.S.I., B.Sc. Math in C.M.I.

The entrances to these programs are far more challenging than usual engineering entrances. Cheenta offers an intense, problem-driven program for these two entrances.

## 2 replies on “Number Theory – Working backward – C.M.I UG -2019”

1,2,4,8,16,32,64,65,130,260

therefore just 9 moves

here it is said to find minimum ways

let 1 was typed now i press another digit key 3 now i again pressed a digit 0 then i press B

hence it proceed that 1-13-130-260 hence it is only 3 moves ………

Google