wunder beta

🧠 Mental Math for Adding and Subtracting

Add and subtract ones from two-digit numbers in your head, and learn to pick the best method — mental or written — for real problems about money and measures.

2
lessons
~20 min
to learn
🔢 Math
subject
Ages 6–12
level
Start the course →

What you’ll learn

  1. Adding and Taking Ones in Your HeadAdd and subtract ones from two-digit numbers mentally by bridging through ten.Mental math bridges the nearest ten. For 36 + 7, step to 40 first (36 + 4), then add 3 to reach 43. For 52 - 4, drop back to 50 first, then take the last 2 to reach 48. The friendly ten makes two-digit sums quick.
  2. Picking the Best MethodChoose a suitable mental or written method for problems involving numbers, money, and measures.Easy hops suit mental math; trickier problems are safer written down. These skills solve real situations: money like 35p - 12p + 5p = 28p, and measures like a 40 cm ribbon minus 6 cm = 34 cm. Pick the tool that fits the problem.

Questions this course answers

Which problem is best to do quickly in your head?

36 + 7 is a single small hop over the ten — perfect for mental math.

Grounded in trusted sources

  • Khan Academy Kids
  • PBS Kids — early math
  • NAEYC — early math learning
  • National Council of Teachers of Mathematics (NCTM)

Every Wunder lesson is built from real, reputable sources — never invented.

Related Math courses

🧠Mental Math with Large Numbers🧩Missing Numbers and Grouping in Addition🧮Multi-Step Addition and Subtraction Problems🏙️Multi-Step Problems with Large Numbers🔢Number Patterns and Sequences🌡️Positive and Negative Numbers🔤Reading and Writing Algebra⚖️Solving Linear Equations

Wunder is a personalized learn-anything platform — tell it any topic and it builds a beautiful, fact-checked course in minutes, with narration, a knowledge check, and a college-style University track.

Browse more Math courses · All topics · Home

© 2026 Wunder Learning LLC · Terms & Privacy