Which sign (+ or -) makes the number sentence true?

key notes :

🌟 Basic Idea

A number sentence is like a math statement (e.g., 5 __ 3 = 8).

We must choose the correct sign:

  • + (plus) → means add
  • − (minus) → means take away

➕ Understanding the Plus Sign (+)

Use + when numbers are joining together

The answer becomes bigger

Example:

5 + 3 = 8 ✔️

➖ Understanding the Minus Sign (−)

Use − when numbers are taking away

The answer becomes smaller

Example:

  • 5 − 3 = 2 ✔️

🔍 How to Choose the Correct Sign

Step 1: Look at the numbers and the answer

Step 2: Think:

  • Is the answer bigger? → use +
  • Is the answer smaller? → use −

Step 3: Try both signs if unsure

🧠 Helpful Tips

  • Count with fingers or objects 🖐️
  • Read the sentence aloud
  • Check your answer after solving ✔️

✏️ Examples

  • 6 __ 2 = 8 → 6 + 2 = 8 ✔️
  • 9 __ 4 = 5 → 9 − 4 = 5 ✔️
  • 3 __ 5 = 8 → 3 + 5 = 8 ✔️
  • 7 __ 3 = 4 → 7 − 3 = 4 ✔️

🎯 Practice Idea

Give students blanks:

  • 4 __ 2 = 6
  • 10 __ 3 = 7

Let them choose + or −

Learn with an example

✈️ Which sign is missing?

17 ___ 3 = 20

  • +
  • –
  • Try both the plus sign and the minus sign.
  • First try the plus sign:17 + 3 = 20
  • Now try the minus sign:17 − 3 = 14
  • The plus sign gives the right answer.

✈️ Which sign is missing?

11__ 7 = 18

  • +
  • –
  • Try both the plus sign and the minus sign.
  • First try the plus sign11 + 7 = 18
  • Now try the minus sign: 11 − 7 = 4
  • The plus sign gives the right answer.

✈️ Which sign is missing?

15 ___ 4 = 19

  • +
  • –
  • Try both the plus sign and the minus sign.
  • First try the plus sign:15 + 4 = 19
  • Now try the minus sign:15 − 4 = 11
  • The plus sign gives the right answer.

Let’s practice!🖊️