The equation would be:
x - 9 < 4
Simplify (add 9)
Solution: x < 13
You want to compare the square root of 55 using "mental math". Start off by choosing two perfect squares that you can think of that are close to 55.
If you don't know perfect squares then start with the number 2 and multiply it by itself. 2 times 2 equals 4, so 4 is a perfect square.
Take the number 3, multiply it by itself, and so on. Do this for all the numbers until you find two perfect squares that are close to 55.
The two perfect squares closest to 55 are the square roots of 49 and 64. Find the square root of these numbers.
√49 = 7
√64 = 8
Calculate how far 55 is from 49 and 64. 55 is 6 digits away from 49 and 9 digits away from 64.
This means the square root of 55 will be closer to the square root of 49; 7. Since we know that it will be closer to 7, you can put the less than sign for your answer.
√55 < 7.7
(The actual square root of 55 is ~7.4, so we were correct in determining the answer without using a calculator!)
Answer: 4.5kg = 9.9208lbs
4.5kg = 158.733oz
1 The volume of the cube is 2 * 2 * 2 or 2 ^ 3 in ^ 3 while the
volume of the large box is 10 * 10 * 10 or 10 ^ 3 in ^ 3.
2 The answer is 125. Just divide the large box to the volume
of the cube 1000 / 8 = 125.
3 The box will hold the same number of balls as small boxes.
With the balls, there is empty space.
4 The answer is still 125. Just find the volume of the box
and of the cube. Divide the box volume by the cube volume.
