Mathematics
Grade 2
15 min
Introduction to Probability
Subtract three-digit numbers
Tutorial Preview
1
Introduction & Learning Objectives
Learning Objectives
Identify the 'total' and a 'part' in a simple probability story.
Set up a three-digit subtraction problem vertically.
Subtract three-digit numbers without regrouping.
Subtract three-digit numbers with regrouping from the tens place.
Subtract three-digit numbers with regrouping from the hundreds place.
Solve word problems to find a missing part of a total group.
Imagine a jar with 250 shiny marbles! ✨ If 120 are red, how many are NOT red? Let's find out!
Today, we will learn a super skill! We will use subtraction to find missing parts of a big group. This helps us understand chances better!
Real-World Applications
Finding out how many tickets are left to sell for a school play.
Figuring out how many pages you have left to r...
2
Key Concepts & Vocabulary
TermDefinitionExample
TotalThe whole amount of items you have all together. 🎈🎈🎈If you have 150 stickers in a book, the total is 150.
PartA smaller group of items from the total. 🎈If 110 of your 150 stickers are smiley faces, 110 is a part.
SubtractTo take away one number from another to find the difference. ➖We subtract to find the part that is left over.
DifferenceThe answer you get when you subtract two numbers. ✅In 10 - 4 = 6, the number 6 is the difference.
Regrouping (or Borrowing)Trading one from a bigger place value for ten of a smaller one. đổiTrading 1 ten for 10 ones so you can subtract.
3
Core Formulas
Finding the Missing Part
Total - Known\ Part = Missing\ Part
Use this rule when you know the total and one part. Subtract to find the other part.
The Regrouping Rule (Tens)
1\ Ten = 10\ Ones
When the bottom digit in the ones place is bigger, you regroup one ten from the tens place.
The Regrouping Rule (Hundreds)
1\ Hundred = 10\ Tens
When the bottom digit in the tens place is bigger, you regroup one hundred from the hundreds place.
4 more steps in this tutorial
Sign up free to access the complete tutorial with worked examples and practice.
Sign Up Free to ContinueSample Practice Questions
Challenging
A large jar contains 925 beads. 450 are round and the rest are star-shaped. If you take out 100 round beads, is it now more likely to pick a round bead or a star-shaped bead?
A.More likely to pick a round bead
B.More likely to pick a star-shaped bead
C.Equally likely to pick either
D.Impossible to tell
Challenging
A farm has 850 animals. 475 are chickens. The rest are sheep. The farmer sells 100 chickens and buys 50 sheep. After this, is it more likely that a random animal on the farm is a chicken or a sheep?
A.More likely to be a chicken
B.Equally likely to be a chicken or a sheep
C.More likely to be a sheep
D.Impossible to be a sheep
Challenging
A bag has 650 letter tiles. 312 are vowels (A, E, I, O, U). The rest are consonants. If you take out 100 consonants and put in 50 vowels, is it now more likely to pick a vowel or a consonant?
A.More likely to pick a vowel
B.More likely to pick a consonant
C.Equally likely to pick either
D.Impossible to pick a vowel
Want to practice and check your answers?
Sign up to access all questions with instant feedback, explanations, and progress tracking.
Start Practicing Free