1. Calculate and display a Scientific Number

Goal: Calculate a value and distinguish it from its display text.

Before you start: The practice level from lesson 0.

The idea you will use

A Scientific Number represents Base × 10^Exponent. Calculation produces a number; a formatter produces display text.

Predict before running

What is 2 × 10³ + 3 × 10³? Does changing decimal places alter the sum?

Build and check

Create the Actor

1. In ScientificNumberPractice/Blueprints, right-click → Blueprint Class → Actor. Name it BP_MiNumero.
2. Double-click to open it. In My Blueprint, open EventGraph. This is where you place the nodes. The Viewport tab of this asset is for components, not calculations.
3. Keep Event BeginPlay. You can remove the Tick and ActorBeginOverlap events from this new Blueprint if you do not use them.
4. Right-click an empty area in the graph and search for Make Scientific Number. The full name identifies the type; make number also works as an alternative search. Choose the one in the Scientific Number category, not Make Vector. Leave Context Sensitive enabled.
5. Set Base = 2 and Exponent = 3. Create another Make Scientific Number with Base = 3 and Exponent = 3.
6. Drag from the output of the first Make Scientific Number and search for Add. Connect the second Make Scientific Number to the other input. The node may appear in compact form as +.
7. Drag from the Add output and search for To Fixed String. Connect it to Value; set Decimal Places = 2.
8. Add Print String. Connect the text output of To Fixed String to In String.
9. Connect the white execution wire as BeginPlay → To Fixed String → Print String. Make Scientific Number and Add are pure nodes and have no white wires.
10. Expand the Print String options and set Duration = 20, Print to Screen = true, and Print to Log = true.
11. Click Compile, check Compiler Results for errors, and save with Ctrl+S. Return to the level and drag BP_MiNumero from the Content Browser into the level. BeginPlay does not run without an instance.
12. Press Play. 5000.00 should appear. Open Window → Developer Tools → Output Log and filter for 5000 to see the Print String output there too.

Inspect the calculation with the debugger

1. Stop Play. Return to BP_MiNumero and change the Base of the second Make Scientific Number from 3 to 4. Compile and run: 6000.00 should appear.
2. Stop Play and disconnect the white wire entering Print String. Compile and run: that message should not appear. Reconnect the wire.
3. Stop Play. Right-click Print String → Add Breakpoint. Press Play.
4. When execution pauses, the editor should highlight that node. In the Blueprint toolbar, select the BP_MiNumero instance under Debug Object / Debug Filter if it is not already selected.
5. Hover over the connected text pin to inspect its value. You can also choose Watch this value from the pin menu. The white wire shows the execution path that ran.
6. Resume and then stop Play. Remove the breakpoint. Set the second Base back to 3 before continuing.

Check your reasoning

See the explanation

The result is 5000. Decimal places change presentation, not the calculated number.

Your turn: Produce 7500 by changing inputs, without typing that result directly into Print String.

Ready to continue when: you can identify the data connections and the execution path that prints the result.