# McGraw Hill Math Grade 7 Lesson 16.3 Answer Key Scientific Notation

Exercises

CONVERT

If the expression is in scientific notation, convert it to a number. If it is a number, convert it to scientific notation. Round all numbers to 6 places to the right of the decimal point when converting to scientific notation.

Question 1.
5 × 105 = ____________
5 × 105 = 500,000
Explanation:
The given expression is in scientific notation. To convert it into a number first we have to solve 105. Here base is 10 and exponent is 5.  So, we have to multiply the base 10 by itself as five times the product is equal to 100,000. Multiply 5 with 100,000 the product is equal to 500,000.

Question 2.
478.23 = _____________
478.23 = 4.7823 x 102
Explanation:
There is a decimal point to the right of the given number. To convert the given number into scientific notation we have to move the decimal point to the left, one place value at a time and we have to count each time we move it.
We have to stop the process when the number is greater than 1 and less than 10. Here I moved two place values. So, the count is 102. The number 478.23 in scientific notation as 4.7823 x 102.

Question 3.
89,786 = _____________
89,786 = 8.9786 x 104
Explanation:
Imagine there is a decimal point to the right of the given number. To convert the given number into scientific notation we have to move the decimal point to the left, one place value at a time and we have to count each time we move it.
We have to stop the process when the number is greater than 1 and less than 10. Here I moved four place values. So, the count is 104. The number 89,786 in scientific notation as 8.9786 x 104.

Question 4.
6.721 × 106 = ____________
6.721 × 106 = 6,721,000
Explanation:
The given expression is in scientific notation. To convert it into a number first we have to solve 106. Here base is 10 and exponent is 6. So, we have to multiply the base 10 by itself as six times the product is equal to 1,000,000. Multiply 6.721 with 1,000,000 the product is equal to 6,721,000.

Question 5.
2.9731 × 10-2 = ______________
2.9731 × 10-2 = 0.029731
Explanation:
The given expression is in scientific notation. To convert it into a number first we have to solve 10-2. Here base is 10 and exponent is -2. So, we have to multiply the base 10 by itself as two times the product is equal to 0.01. Multiply 2.9731 with 0.01 the product is equal to 0.029731.

Question 6.
691,273 = _____________
691,273 = 6.91273 x 105
Explanation:
Imagine there is a decimal point to the right of the given number. To convert the given number into scientific notation we have to move the decimal point to the left, one place value at a time and we have to count each time we move it.
We have to stop the process when the number is greater than 1 and less than 10. Here I moved five place values. So, the count is 105. The number 691,273 in scientific notation as 6.91273 x 105.

Question 7.
5,9178 × 10-3 = ____________
5,9178 × 10-3 = 0.0059178
Explanation:
The given expression is in scientific notation. To convert it into a number first we have to solve 10-3. Here base is 10 and exponent is -3. So, we have to multiply the base 10 by itself as three times the product is equal to 0.001. Multiply 5,9178 with 0.001 the product is equal to 0.0059178.

Question 8.
8.72345 × 1010 = ______________
8.72345 × 1010 = 87,234,500,000
Explanation:
The given expression is in scientific notation. To convert it into a number first we have to solve 1010. Here base is 10 and exponent is 10. So, we have to multiply the base 10 by itself as ten times. Multiply 8.72345 with 1010 the product is equal to 87,234,500,000.

Question 9.
6,664,475 = _____________
6,664,475 = 6.664475 x 106
Explanation:
Imagine there is a decimal point to the right of the given number. To convert the given number into scientific notation we have to move the decimal point to the left, one place value at a time and we have to count each time we move it.
We have to stop the process when the number is greater than 1 and less than 10. Here I moved six place values. So, the count is 106. The number 6,664,475 in scientific notation as 6.664475 x 106.

Question 10.
.0005123 = ______________
.0005123= 5.123 x 10-4
Explanation:
There is a decimal point to the right of the given number. To convert the given number into scientific notation we have to move the decimal point to the right, one place value at a time and we have to count each time we move it.
We have to stop the process when the number is greater than 1 and less than 10. Here I moved four place values to left . So, the count is 10-4. The number .0005123 in scientific notation as 5.123 x 10-4.

Question 11.
8.9 = ______________
8.9 = 8.9 x 100
Explanation:
There is a decimal point to the right of the given number. The number 8 is greater than 1 and less than 10. Here I moved zero place values to right . So, the count is 100. The number 8.9 in scientific notation as 8.9 x 100.

Question 12.
100.235 = _______________
100.235 = 1.00235 x 102
Explanation:
There is a decimal point to the right of the given number. To convert the given number into scientific notation we have to move the decimal point to the left, one place value at a time and we have to count each time we move it.
We have to stop the process when the number is greater than 1 and less than 10. Here I moved two place values. So, the count is 102. The number 100.235 in scientific notation as 1.00235 x 102.

Question 13.
963,764 = _____________
963,764 = 9.63764 x 105
Explanation:
Imagine there is a decimal point to the right of the given number. To convert the given number into scientific notation we have to move the decimal point to the left, one place value at a time and we have to count each time we move it.
We have to stop the process when the number is greater than 1 and less than 10. Here I moved five place values. So, the count is 105. The number 963,764 in scientific notation as 9.63764 x 105.

Question 14.
4.6554 = _____________
4.6554 = 4.6554 x 100
Explanation:
There is a decimal point to the right of the given number. The number 4 is greater than 1 and less than 10. Here I moved zero place values to right . So, the count is 100. The number 4.6554 in scientific notation as 4.6554 x 100.

Question 15.
789.23 = _______________
789.23 = 7.8923 x 102
Explanation:
There is a decimal point to the right of the given number. To convert the given number into scientific notation we have to move the decimal point to the left, one place value at a time and we have to count each time we move it.
We have to stop the process when the number is greater than 1 and less than 10. Here I moved two place values. So, the count is 102. The number 789.23 in scientific notation as 7.8923 x 102.

Question 16.
15,896,000,000,000 = ______________
15,896,000,000,000 = 1.5896 x 1013
Explanation:
Imagine there is a decimal point to the right of the given number. To convert the given number into scientific notation we have to move the decimal point to the left, one place value at a time and we have to count each time we move it.
We have to stop the process when the number is greater than 1 and less than 10. Here I moved thirteen place values. So, the count is 1013. The number 15,896,000,000,000 in scientific notation as 1.5896 x 1013.

Question 17.
8,999,345,000 = ________________