Home Activity: Percent Applications

A fun 10-minute activity to do with your child!

Dear Family,

Your child is learning about percent applications - using percentages to calculate tax, tips, discounts, and interest. These are real-world skills your child will use for the rest of their life! No math expertise needed - you'll learn together!

Activity 1: Restaurant Tip Calculator 10 min

You'll Need:

  • A restaurant menu or receipt (or make up prices)
  • Paper and pencil
  • Calculator (optional)

Pick a meal total. Example: "Our dinner costs $45 before tip and tax."

Calculate different tip amounts: "What's 15% tip? 18%? 20%?"

Show the process: "For 20%, convert to decimal: 0.20. Then multiply: 0.20 x $45 = $9."

Quick trick: "To find 10%, just move the decimal one place left. So 10% of $45 is $4.50. Double it for 20%: $9!"

Add tax: "If tax is 7%, what's 0.07 x $45? ($3.15) What's the grand total?"

Key Phrase to Use:

"To find a percent of a number, convert the percent to a decimal (divide by 100), then multiply. 20% of $45 = 0.20 x 45 = $9."

Activity 2: Sale Price Detective 10 min

You'll Need:

  • Sale advertisements or online store
  • Paper and pencil

Find an item on sale. Example: "This jacket was $80, now 30% off."

Calculate the discount: "30% of $80 = 0.30 x 80 = $24 off."

Find the sale price: "$80 - $24 = $56."

Shortcut method: "If it's 30% OFF, you pay 70%. So 0.70 x $80 = $56!"

Challenge: "If something costs $63 after a 10% discount, what was the original price?" (Hint: $63 is 90% of the original)

Real-World Connection:

"When something is 25% off, you're paying 75% of the price. Subtracting the percent off from 100% gives you the percent you pay!"

Activity 3: Percent Change in Real Life 5 min

You'll Need:

  • Any two numbers to compare (prices, scores, etc.)
  • Paper and pencil

Find two values to compare. Example: "Last month, gas was $3.00. Now it's $3.60."

Find the change: "$3.60 - $3.00 = $0.60 increase."

Divide by the ORIGINAL: "$0.60 / $3.00 = 0.20 = 20% increase."

Important rule: "Always divide by the ORIGINAL amount, not the new amount!"

Important Reminder:

"Percent change = (New - Original) / Original x 100. The key is dividing by the ORIGINAL value, not the new one!"

Questions to Ask Your Child

You're Making a Difference!

Percent calculations are some of the most useful math skills in daily life. From shopping sales to restaurant tips to understanding loans, your child is learning math they'll use forever. Thank you for being part of their learning journey!

Para Familias Hispanohablantes:

Su hijo esta aprendiendo sobre aplicaciones de porcentajes. Para encontrar un porcentaje de un numero, convierta el porcentaje a decimal (divida entre 100) y multiplique. Por ejemplo: 20% de $50 = 0.20 x 50 = $10. Para descuentos: si algo tiene 30% de descuento, usted paga 70%. Para cambio porcentual: (Nuevo - Original) / Original x 100. Siempre divida por el valor ORIGINAL. Para interes simple: I = P x r x t (Principal x tasa x tiempo). Practique calculando propinas en restaurantes o precios de venta en tiendas. Gracias por apoyar el aprendizaje de su hijo!