Reversing Calculations & Function Machines Learning Pages

Your Turn!! (no calculator)

Above is a function machine.

a) Complete the flow chart for its inverse function machine. Use the symbol pop-up menu to the right where needed.

Input <- π + − ÷ × < > ≤ ≥ π <- π + − ÷ × < > ≤ ≥ π <- Output

b) If the output of the original function machine is 118, find the input. π + − ÷ × < > ≤ ≥ π

Your Turn!!

A skip company charges £120 for delivering the skip and £15 per day of rental of the skip.

The skip company charges John £270 for a skip. 

Find how long John rented the skip for in days without using trial and error. π + − ÷ × < > ≤ ≥ π days

Your Turn!! (no calculator)

Given that 12 × 999 = 11,988, find the following, writing your answers without commas or spaces.

a) 11988 ÷ 1.2 π + − ÷ × < > ≤ ≥ π

b) 11.988 ÷ 12 π + − ÷ × < > ≤ ≥ π

RAPID TEST

1) The above shows a function machine.  If the output is 87, what is the input? π + − ÷ × < > ≤ ≥ π

2) John mends computers and charges £15.75 for the first hour plus £10.50 for each additional hour.

John charged Caroline £131.25.

How many total hours, including the first, did John work for Caroline? π + − ÷ × < > ≤ ≥ π hours

3) Given that 123 × 789 = 97,047, find 9704.7 ÷ 789 without using a calculator. π + − ÷ × < > ≤ ≥ π