please explain me in detail

[vista]

1) All the nine digits are arranged here so as toform four square numbers:9,81,324,576


How would you put them together so as to form a single smallest square number and a single largest possible square number?


2)A wholesale merchant came to me one day and posed this problem.Everyday in his business he had to weigh amounts fromm one pound to hundred and twenty-one pounds, to the nearest pound.To do this, what is the minimum number of weighs he needs and how heavy should each weight be?

3)There are eleven different ways of writing 100 in the form of mixed numbersusing all the nine digits once and only once.Ten of the ways have two figures in the integral part of the number,but the eleventh expression has only one figure there.Can you find all the eleven expressions?

[ggk87]

1) All the nine digits are arranged here so as toform four square numbers:9,81,324,576


How would you put them together so as to form a single smallest square number and a single largest possible square number?


2)A wholesale merchant came to me one day and posed this problem.Everyday in his business he had to weigh amounts fromm one pound to hundred and twenty-one pounds, to the nearest pound.To do this, what is the minimum number of weighs he needs and how heavy should each weight be?


3)There are eleven different ways of writing 100 in the form of mixed numbersusing all the nine digits once and only once.Ten of the ways have two figures in the integral part of the number,but the eleventh expression has only one figure there.Can you find all the eleven expressions?

[ggk87]

the answer is given in shakunthala devi book ,but I want to know how to arrive at the answer