$MathMaster logo$

MathMaster

Home
general
4x21 using doubling twice strategy

Question

4x21 using doubling twice strategy

50

likes

250 views

Answer to a math question 4x21 using doubling twice strategy

$Expert avatar$

4.9

87 Answers

1. First doubling:

4 \times 21 = (2 \times 21) \times 2

2. Simplify inside the parentheses:

2 \times 21 = 42

3. Second doubling:

42 \times 2 = 84

Answer:

4 \times 21 = 84

Frequently asked questions (FAQs)

Question: Find the product of a mixed number, 3 and 1/4, and a real number, pi, after factoring the number 72.

+

Math Question: What is the value of the integral of x^2 + 3x + 2 with respect to x, using the power rule?

+

Find the value of y if x=4 in the circle function x^2+y^2=16.

+

New questions in Mathematics

𝑦 = ( 𝑥2 − 3) (𝑥3 + 2 𝑥 + 1)

a ferry travels 1/6 of the distance between two ports in 3/7 hour. The ferry travels at a constant rate. At this rate, what fraction of the distance between the two ports can the ferry travel in one hour.

Revenue Maximization: A company sells products at a price of $50 per unit. The demand function is p = 100 - q, where p is the price and q is the quantity sold. How many units should they sell to maximize revenue?

Find the equation of the normal to the curve y=x²+4x-3 at point(1,2)

3(4×-1)-2(×+3)=7(×-1)+2

A car that starts from rest moves for 11 min, reaching a speed of 135 km/h, calculate the acceleration it had

The director of a company must transfer 6 people from the human resources department to the sales department, in order to sustain sales during the month of December. What is the probability that he will transfer only 2 of them?

Margin of error E=0.30 populations standard deviation =2.5. Population means with 95% confidence. What I the required sample size (round up to the whole number)

The function g:Q→Q is a ring homomorphism such that g(3)=3 and g(5)=5. What are the values of g(8) and g(9)?

The thermal representation f(x) = 20 times 0.8 to the power of x is known from an exponential function f. Specify the intersection point with the y-axis

In an audience of 4000 people, 2 people are chosen, at random, to appear on stage. How many ways can the people be chosen?

What is 75 percent less than 60

a survey showed that 3 out of 7 voters would vote in an election. based on this survey, how many people would vote in a city with 25,000 people?

nI Exercises 65-68, the latitudes of a pair of cities are given. Assume that one city si directly south of the other and that the earth is a perfect sphere of radius 4000 miles. Use the arc length formula in terms of degrees to find the distance between the two cities. 65. The North Pole: latitude 90° north Springfield, Illinois: latitude 40° north

A person runs 175 yards per minute write a variable that represents the relationship between time and distance

Find the equation of a straight line that has slope 3 and passes through the point of (1, 7) . Write the equation of the line in general forms

A triangle is cut by a line s parallel to the base in such a way that it divides the side of the triangle into parts in the ratio of 2 : 3. Find the other side of the triangle if it is known that the line s divides it into parts whose length is 5 cm.