Training module

Google Sheets for payroll and compound interest

Google Sheets para sa payroll at compound interest

Teach learners to build a digital payslip and a compound-interest table with formulas, so they can prepare the Term 1 performance task and check Term 3 computations.

Time: 50 minutes
For: Grade 11 General Mathematics teachers (Term 1, Weeks 1–2 and 5; Term 3, Weeks 1–4)
Tools: Google Sheets, Spreadsheet

You will be able to

Build a payroll sheet that computes gross pay, overtime, SSS/PhilHealth/Pag-IBIG deductions and net pay with formulas.
Build a compound-interest and amortisation table with absolute and relative references.
Choose between Google Sheets and an offline spreadsheet app depending on connectivity.

Module

Online or offline?

Google Sheets needs an account and a connection, but it is free and collaborative. If connectivity is poor, the same formulas work in LibreOffice Calc (free, offline) or the spreadsheet app already on most phones. Teach the formulas, not the brand.

A payslip in eight cells

A1 Daily rate, A2 Days worked, A3 Overtime hours. Gross = A1*A2 + A3*(A1/8)*1.25.
Deductions: enter the current SSS, PhilHealth and Pag-IBIG contribution rates in separate cells so learners can update them when DepEd or the agencies change rates.
Withholding tax: use nested IF for the tax brackets, or a lookup table with VLOOKUP.
Net pay = Gross − total deductions. Format currency as ₱ with two decimals.

Item	Formula
Gross pay	=A1A2 + A3(A1/8)*1.25
SSS	=MIN(Gross, cap)*rate
Net pay	=Gross - SUM(deductions)

Compound interest, one row per period

Set up columns Period, Opening balance, Interest, Closing balance. Interest = Opening × rate/periods per year, with the rate in an absolute reference such as $B$1 so it fills down. Let learners drag the formula for 10 years and compare the closing balance with the formula A = P(1 + r/n)^{nt}.

A = P\left(1+\frac{r}{n}\right)^{nt}

Amortising a loan

Add a Payment column using the PMT function, then show Interest, Principal and Balance per month. Learners discover that early payments are mostly interest, which connects to the Term 3 lesson on consumer loans and to the loan calculator in this site's Interactive Tools.

R = \frac{P\,i}{1-(1+i)^{-n}}

Charts for the financial report

Evaluate

Insert a line chart of Closing balance vs Period, and a column chart comparing simple and compound interest. The Term 1 performance standard asks for a digital financial report with graphs, equations and a justified decision; the chart plus a one-paragraph recommendation is enough.

Try it

Build the payslip sheet with this year's contribution rates and verify one case by hand.
Create a 12-period compound-interest table for ₱10,000 at 6% compounded monthly and compare the final value with the formula.
Prepare a one-page guide for learners who only have a phone spreadsheet app.