4. Write the following number in generalized form: 28
Answers
Answer:
Step-by-step explanation:
A number is said to be in a generalized form if it is expressed as the sum of the product of its digits with their respective place values.
Thus, a two-digit number having a and b as its digits at the tens and the ones places respectively is written in the generalized form as 10a + b, i.e., in general, a two-digit number can be written as 10a + b, where ‘a’ can be any of the digits from 1 to 9 and ‘b’ can be any of the digits from 0 to 9.
Similarly, a three-digit number can be written in the generalized form as 100a + 10b + c, where ‘a’ can be any one of the digits from 1 to 9 while ‘b’ and ‘c’ can be any of the digits from 0 to 9.
For example:
The generalized forms of a few numbers are given below:
56 = 10 × 5 + 6;
37 = 10 × 3 + 7;
90 = 10 × 9 + 0;
129 = 100 × 1 + 2 × 10 + 9;
206 = 100 × 2 + 10 × 0 + 6;
700 = 100 × 7 + 10 × 0 + 0.
Word problems on playing with numbers:
1. What is the original number, if the sum of the digits of a two-digit number is seven. By interchanging the digits is twenty seven more than the original number?
Solution:
Let the original number be 10a + b.
Then, ‘a’ is the tens digit and ‘b’ is the units digit.
Since the sum of the digits is 7,
Therefore a + b = 7,
i.e., b = 7 - a..
So, the original number is 10a + (7 - a).
Therefore, the number obtained by interchanging the digits is
10(7 - a) + a,
and so we have {10(7 - a) + a} — {10a + (7 - a)} = 27.
Solving this equation, we get
a = 2.
And so, b = 7 - 2
= 7 - 2
= 5.
Hence, the original number is 10a + b = 20 + 5 = 25.
Step-by-step explanation:
The answer is 5×5+3
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