Grade 2 (age 7-8)

grade 2 Addition & Subtraction with Carrying

Addition & Subtraction with Carrying

When you add or subtract two-digit numbers, a single column sometimes holds too much or too little. If the ones reach ten, you carry one over to the tens; if the ones are too small to subtract, you borrow ten from the tens. Packing apples ten to a basket is a quick way to feel why that promise is needed. Slide the two numbers and watch, column by column, how carrying and borrowing play out in a vertical sum.

Why Do We Need Carrying?

🧺 Let's Put Apples in Baskets!

①One basket holds up to 10 apples

②7 + 6 = 13? The basket overflows!

③Move 10 to a new basket, leave 3

④This is "carrying"

Addition with Carrying

First Number47

Second Number36

💡 Carrying Steps

①Add ones place first

②If ≥ 10 → carry 10 to next place, write only the rest

③Add tens places + 1 (the carry)

Subtraction with Borrowing

Larger63

Subtract28

💡 Borrowing Steps

①When you can't subtract ones

②Borrow 10 from tens place

③Add 10 to ones, subtract

④Tens place decreases by 1

⑤If the subtracted number is larger, the picture swaps so the larger minus the smaller is shown

Summary

Addition with Carry

47 + 36 → Ones: 7+6=13 (write 3, carry 1) → 83

Sum ≥ 10 → carry 10 to next place

Subtraction with Borrow

63 - 28 → Ones: 3<8 → 13-8=5, Tens: 5-2=3 → 35

Can't subtract → borrow 10 from next place

🎯 Remember!

①Always start from ones place

②Carry: > 10 → carry 1

③Borrow: not enough → borrow 10

④Mark carries/borrows to avoid mistakes

⑤Check: result + subtractor = original

Examples and Unit Test

Example 1

Calculate 58 + 27 using vertical addition.

Ones: 8 + 7 = 15. Write 5 and carry 1 to the tens.

Tens: 5 + 2 + 1(carry) = 8. So 58 + 27 = 85.

▸ 85

When the ones sum is 10 or more, carry 1 to the tens place.

Example 2

Calculate 72 − 35 using vertical subtraction.

Ones: you cannot take 5 from 2. Borrow 10 from the tens: 12 − 5 = 7.

Tens: after lending, 7 − 1 = 6, then 6 − 3 = 3. So 72 − 35 = 37.

▸ 37

When the ones cannot subtract, borrow 10 from the tens place. Check: 37 + 35 = 72.

Unit Test

What is the value of 46 + 38?

①74

②84

③714

④88

▸ ② 84

Ones: 6 + 8 = 14. Write 4 and carry 1.

Tens: 4 + 3 + 1 = 8. So 46 + 38 = 84.

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Four-digit Numbers

Multiplication Basics