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## Maths Worksheets For Class 4

Karl Said:

How do you solve 4^x=8?

You use logarithms (in particular the change of base formula)

change of base = log(value) / log(base)

base = 4 and value = 8

so

x = log(8) / log(4) = 1.5

Edit: You could also do like how you did it

4^x = 8 is the same as

(2^2)^{x} = 2^3

Since (2^2)^{x} = 2^{2x} we can write

2^{2x} = 2^{3}

Since the base is the same (both have a base of 2)

the exponents must be equal so

2x = 3

Solve for x (divide both sides by 2 to get)

x = 3/2 [ which 3/2 = 1.5]

That is the way that you did the problem.

Lucille Said:

Need help with a Java worksheet?

1) System.out.print(1 % 5);
1 (% is mod operator.. result will be reminder of division)

2) System.out.print(5 % 2);
1

3) System.out.print(7.2 % 3);
1.2

4) System.out.print( 'A' + 9 );
74

5) System.out.print( 9.3 % 3 );
0.3

6) System.out.print( 'c' + 5);
104

7) System.out.print( Math.pow (3, 3) );
27 (pow is for power)

8) System.out.print( Math.ceil (3.4) );
4 (rounds up)

9) System.out.print( Math.floor (4.6) );
5 (rounds down)

10) System.out.print( Math.sqrt (12) );
3.4641016151377544

11) System.out.print( Math.round (12.34) );
12 (normal rounding)

12) System.out.print( Math.round (12.56) );
13

13) System.out.print( Math.max(12, 34) );
34 (returns maximum value)

14) System.out.print( Math.min(12, 34) );
12 (returns minimum value)

15) System.out.print( Math.max(12.3, 45.6) );
45.6

16) System.out.print( Math.min(12.3, 45.6) );
12.3

17) System.out.print( Math.abs(-213) );
213 (absolute value)

18) System.out.print( Math.abs(213) );
213

19) System.out.print( Math.ceil (math.sqrt(17) ) );
5 ('math' should be 'Math'.. Java is case sensitive)

20) System.out.print( Math.random() );
returns a random decimal number less than 1.0 and greater than or equal to 0.0

21) System.out.print( Math.random() * 10 );
random number less than 10 and greater than or equal to 0

22) System.out.print( Math.random() * 20 + 10 );
random number less than 30 and greater than or equal to 10

Glen Said:

Where can i find Class 4 CBSE on line help for english, math worksheets