Using function machines with a single operation to find outputs from inputs, and working backwards to find inputs.
Where your child meets this in real life: Understanding processes with inputs and outputs, like vending machines or recipes
Each SEAG paper has 28 maths questions. Questions 29 to 50 are multiple choice with five possible answers, and questions 51 to 56 need a short written answer. With 56 questions in 60 minutes across English and maths, that is about a minute per question.
SEAGReady breaks one-step function machines into 2 steps, taught in order so each skill builds on the last.
Find the output when given an input and a single operation in a function machine
Find the input when given an output and a single operation by working backwards using inverse operations
Try three free questions from our one-step function machines course. They start easy and get harder, so you can see where your child's confidence runs out. If they manage the last one without a hint, this topic is probably secure. If not, the steps above show where to start.
Charlotte puts 8 into the function machine shown. What output comes out?
At a sweet shop, there is a pricing machine that multiplies by 8 to show the cost in pence. If the display shows 72p, how many items were entered?
Reece is testing a function machine. He notices that when he puts in 5, the output is 40. When he puts in 8, the output is 64. What operation does the function machine do?
This is the exact interactive worked example your child sees in SEAGReady. Step through it and watch the method build up.
Emma is using a function machine. The machine takes a number, multiplies it by 4, and gives the output.
If she puts in 7, what number comes out?
7 → ×4 → ?
The input is 7
Step 1 of 3
Emma is using a function machine. The machine takes a number, multiplies it by 4, and gives the output.
If she puts in 7, what number comes out?
When Emma puts in 7, the machine gives 28.
The key insight: A function machine always does the same thing to any number you put in!
Common mix-up: 7 + 4 = 11. The operation is multiply (×4), not add (+4). Read the operation symbol carefully.
These are the misconceptions we see most often in one-step function machines, including the ones our practice questions are specifically designed to catch.
Struggling with one-step function machines? The real gap is often in one of these earlier topics.
Sitting the SEAG test this November? Read our last-month revision plan, Paper 1 vs Paper 2 and test day guide.
SEAGReady finds the exact step where your child gets stuck, teaches it with worked examples like the one above, and brings it back for review so it sticks.
Free to start · no card needed