Q Mintz is one of the largest and fastest-growing online platforms dedicated to high-quality Multiple Choice Questions (MCQs) for students, job seekers, and professionals. Our mission is to provide reliable, accurate, and up-to-date learning material that helps users prepare effectively for school exams, competitive tests, departmental assessments, and job interviews.
At Q Mintz, we believe that consistent practice leads to success.
Search
What is 40 multiplied by 40?
A. 1200
B. 1600
C. 1400
D. 1800
Correct Answer Is Option = 1600
Notes / Explanation
When the number forty is multiplied by forty, the result is one thousand six hundred, and this calculation, which is an example of a number multiplied by itself, provides a good opportunity to reflect on multiplication and on the idea of a square number. When a number is multiplied by itself, the result is called the square of that number, so that one thousand six hundred is the square of forty, and multiplying forty by forty is the same as squaring forty. Such calculations appear frequently in mathematics, for example in problems involving areas, since the area of a square shape is found by multiplying the length of its side by itself, so that a square with sides of forty units has an area of one thousand six hundred square units. This particular calculation is quite easy to work out, because it involves round numbers. One simple way to work it out is to note that forty is four tens, so that forty multiplied by forty is the same as four multiplied by four, which is sixteen, followed by the appropriate number of zeros from the tens, giving one thousand six hundred. Another way to see it is to note that forty multiplied by forty can be worked out by first multiplying forty by four to get one hundred and sixty, and then multiplying by ten to get one thousand six hundred. Multiplying by numbers that are multiples of ten is made easier by the fact that one can multiply the simple numbers and then account for the zeros. A good command of multiplication, including the multiplication of round numbers and the squaring of numbers, is very useful, both for solving problems in mathematics and for dealing with many practical situations. Knowing the squares of the round numbers, such as ten, twenty, thirty, forty, fifty and so on, is particularly useful, since these appear often and are easy to work out, being the square of the simple number followed by the appropriate zeros. Questions testing the ability to carry out such calculations are common in examinations. For PPSC and other competitive examinations, the key points to remember are that forty multiplied by forty equals one thousand six hundred, that a number multiplied by itself gives its square, so that one thousand six hundred is the square of forty, that this calculation is made easy by the fact that forty is a round number, being four tens, so that one can multiply four by four to get sixteen and then add the zeros, and that knowing the squares of the round numbers is useful because they appear often and are easy to work out.
