21.

Given the numbers 3.75 X 10^-7, $3\frac{3}{4}$ X 10^-7, 375 X 10^-9, and $\frac{3}{8}$ X 10^-7. Which of these is not equal to 0.000000375?

• 375 X 10^-7

• $\frac{3}{8}$ X 10^-7

• 3.75 X 10^-7

• $3\frac{3}{4}$ X 10^-7

Given n numbers, n > l, of which, one is 1-$\frac{1}{\mathrm{n}}$ and all others are 1's. The mean of the n numbers is

• n-$\frac{1}{\mathrm{n}}$

• 1-$\frac{1}{{\mathrm{n}}^2}$

• 1

• n-$\frac{1}{{\mathrm{n}}^2}$

Salman solves -3-4=+7. The error is committed as

• Salman needs to practise solving problems of similar type

• Salman has not understood the concept of multiplication of integers

• Salman is careless

• Salman is not clear about the concept of addition of integers

Problem-solving method is the

• teaching the development of mathematics within a historical, social and cultural context.

• cultivation of mathematical ingenuity, creativity and heuristic thinking by making students open-minded.

• gradual and systematic guiding through the hierarchy of mathematical notions, ideas and techniques.

• teaching of mathematical results, definitions and concepts by repetition and memorisation.

Mr Manish used lots of manipulatives, Maths Lab activities and ICT activities to clarify the concept of 'Symmetry'. Mr Manish wants to pass time so that he can avoid teaching of next topic, as

• it is not of his interest

• cater to kinesthetic learners only

• cater to students of all learning styles

• be popular amongst his students

If A= $\frac{3}{4}+\frac{5}{6}$ ,B= 3$÷$$\left[\left(4÷5\right)÷6\right]$ ,C=$\left[3÷\left(4÷5\right)÷6\right]$ and D=$3÷4\left(5÷6\right)$ , then

• A and D are equal

• All are equal

• A and B are equal

• A and C are equal

Shown here are expressions given to Seema, Anees, Asha and Tessy with their answers

Seema 4X1+8$÷$2=8
Anees 6+4$÷$2-1=4
Asha 9+3X2-4$÷$2=10
Tessy 27$÷$3-2X3=21

Who has got the correct answer?

• Asha

• Tessy

• Seema

• Anees

When the number 3⁹⁸ is divided by 5, the remainder is

• 3

• 1

• 4

• 2

Which of the fractions is the least?

• $\frac{99}{100}$

• $\frac{68}{69}$

• $\frac{24}{25}$

• $\frac{10}{11}$

In the figure, in $△$PQR and $△$TQR, PQ = TR and PR = TQ. Which of the following statements is true?

• $△$PQR$\cong$$△$RQT

• $△$PQR$\cong$$△$QTR

• $△$PQR$\cong$$△$TRQ

• $△$PQR$\cong$$△$TQR