mental math strings

Mental Math Strings

1. Start with the number of sides in a pentagon.

2. Add the number of sides in a triangle.3. Divide by the number of sides in an

octagon.4. Multiply by the number of diagonals in a

rectangle.5. Add the minimum number of points

needed to determine a line. 6. Add the square of the number of angles

in a parallelogram.7. Divide by the square root of the number

of sides in a trapezoid.

Mentally:

Start with the number of sides in a pentagon. 5Add the number of sides in a triangle. 5 + 3 = 8Divide by the number of sides in an octagon. 8/8 = 1Multiply by the number of diagonals in a rectangle 1 * 2 = 2Add the minimum number of points needed to determine a line.

2 + 2 = 4Add the square of the number of angles in a parallelogram

4 + 42 = 20Divide by the square root of the number of sides in a trapezoid

20/2 = 10

1.Consider y = 6x + 12.2.Write down the y-

intercept.3.Add the slope of the line.4.Divide that by the x-

intercept.5.Add the value of y when x

= ½ .6.Add the value of x when y

is 6.7.Multiply that by the

square of the zero of the function.

Using Pencil and Paper:

Consider y = 6x + 12Write down the y-intercept.

12

Add the slope of the line. 12 + 6 = 18

Divide that by the x-intercept.

18/-2 = -9

Add the value of y when x = ½ .

-9 +15 = 6

Add the value of x when y is 6.

6 + -1 = 5

Multiply that by the square of the zero of the function.

5 * 4 = 20

1.Write down the tan 45° .2.Divide that by the sin 30° .3.Cube this value.4.Multiply that result by cos

120° .5.Add the sin 270° .6.Multiply by cos 180° .7.Multiply by 5π/4 .8.Call that result “x” and find tan(x).