Question

the estimated sum of 45 and 39 is​

Answer 1

Concept:

For whole numbers, the following rules apply:

Always use the smallest place value to get an accurate result.

To the right of the number that is being rounded off, locate the next smaller area. For instance, look for a digit in the one place if you are rounding off a digit from the tens place.

The digit in the smallest location is unaffected if it is less than 5 in number. Rounding down is the process of reducing a number by any number of digits until it equals zero.

The digit in the smallest location is added with +1 if it is bigger than or equal to 5. Any additional digits become zero, a process known as rounding up.

Given:

45 and 39

Find:

Find the estimated sum of 45 and 39 is​

Solution:

estimate of 45 is 50

estimate of 39 is 40

sum =40+50

sum =90

Therefore, the estimated sum of 39 and 45 is 90

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Answer 2

Answer:

84

Step-by-step explanation:

The sum is an arithmetic operation that adds two numbers to produce the final result. Let X be the first number and Y be the second. X + Y = Z is the outcome of adding X and Y.

Line up the numbers

$\begin{array}{r}45 \\+\quad 39\end{array}$

Add each column of digits, starting on the right and working left. If the sum of a column is more than ten, 'carry' digits to the next column on the left.

Add the digits of the bolded column: 5+9=14

$\begin{array}{r}45 \\+\quad 39\end{array}$

Carry 1 to the column on the left and write 4 in the bolded column

$\begin{array}{r}1 \\45 \\+\quad 39 \\\\\end{array}$

________

         4

Add the digits of the bolded column: 1+4+3=8

$\begin{array}{r}1 \\45 \\+\quad 39 \\\end{array}$

_______

84

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