YAYA JOURNAL · Yaya Blog
Turn hard problems into
steps you can follow
Practical guides for browser tools, debugging, and productivity — with clear steps, real examples, and reusable checklists.
Featured Compound Interest Calculator with Contributions
Estimate compound interest from a principal, nominal annual rate, compounding frequency, and end-of-period contributions. See formulas, examples, and limits.
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Meal Budget With Tax and Tip: $50 Example
Work backward from an all-in restaurant budget to find the maximum menu price. See Ria's $50 DC example, including 10% tax and a 15% tip, step by step.
Unit Price Calculator: Compare Grocery Package Sizes
Learn how to compare grocery package sizes using price per 100 g, liter, or item. Work through a 12 oz versus 20 oz example and avoid common unit-price mistakes.
Fraction Calculator: Add, Simplify, and Convert Decimals
Add mixed numbers, simplify with a GCD, and convert a finite decimal to a fraction. We ran the live page defaults on 10 Oct 2026: 2/3 plus 1 1/4 is 23/12.
How to Calculate a Tip on a Taxed Bill
Calculate a tip on the after-tax bill, then split the total evenly. On the page default, $80 at 20% is a $16 tip, a $96 total, and $48 for each of two people.
Percentage Calculator: Percent Of, Increase, and Change
Use four percent formulas on one page: share of a total, percent of a number, increase or decrease, and change from A to B. We checked the live defaults.
Loan Calculator: Monthly Payment, Interest, and Two Methods
Estimate a fixed-rate loan's monthly payment and total interest, then compare level payment with equal principal on the same amount, rate, and full term.
What Grade Do I Need on My Final? Weighted Grade Math
Find what grade you need on your final from weighted scores and leftover course weight. Work a 70% example and see when a 90% target is already out of reach.
Sales Tax Calculator: Add Tax or Remove It From a Total
Learn the two formulas for adding sales tax and backing it out of a tax-inclusive price, with examples and clear limits.
Savings Goal Calculator: Estimate Monthly Savings and Time to Goal
Learn how a savings goal calculator estimates monthly contributions, time to goal, and fixed-rate growth—and where the estimate stops.