Integers · Meet the integers · 1.2

The number line.

On the number line, integers march left to right: negatives to the left of 0, positives to the right. Moving right adds 1; moving left subtracts 1.

01 / THE IDEA

See it work.

On the number line

Start at 0, hop right 0.

0 + 0 = 0

-1010

Watch the method

The number line

The next integer after −4 is −3 — one step right.

1 / 1
(−4)→  ?(-4) \to \;?
1

One step on the line

The successor is one step to the right (+1).

(−4)+1=−3(-4) + 1 = -3
02 / YOUR TURN

Practice until it feels automatic.

Your turn

Work it out.

Type a whole number — negatives allowed, e.g. -7.

streak 0
best 0
… =
— / WHY IT WORKS

The idea underneath.

Left to right

Each step right is +1, each step left is −1. −4, −3, −2, −1, 0, 1, 2 … in order.

Why it works

A thermometer laid on its side.

03 / WORKED EXAMPLES

From easy to tricky.

EX 1easy

Which integer comes just after -1?

1

One step on the line

The successor is one step to the right (+1). (-1) + 1 = 0

EX 2medium

Which integer comes just before 2?

1

One step on the line

The predecessor is one step to the left (−1). 2 - 1 = 1

EX 3hard

Which integer comes just after 7?

1

One step on the line

The successor is one step to the right (+1). 7 + 1 = 8

04 / COMMON TRAPS

Where students slip.

Trap

Thinking −3 is less than −4.

Fix

−3 is to the right of −4, so it is greater.

Trap

Counting the wrong way for negatives.

Fix

Right always means add 1.

05 / QUIZ

Test yourself.

The Test

12 problems across three tiers. Auto-graded on submit. Hints and a full walkthrough on every question. Your work is saved on this device — sign in to keep it across devices.

0/12Answered
How to answerType just the value. Formatting won't trip you up — we ignore spaces, capital letters, commas, and subscript style, so t₁ = 5, d = 3 and t1=5,d=3 both count. For a list of numbers, separate them with commas (e.g. 3, 10, 17).
Core

Core (4)

C1

Which integer comes just after -1?

Need a hint?
  • “Just after” means one step right (+1).
  • Right is the bigger direction.
C2

Which integer comes just before 6?

Need a hint?
  • “Just after” means one step right (+1).
  • Right is the bigger direction.
C3

Which integer comes just before -5?

Need a hint?
  • “Just after” means one step right (+1).
  • Right is the bigger direction.
C4

Which integer comes just before 12?

Need a hint?
  • “Just after” means one step right (+1).
  • Right is the bigger direction.
Apply

Apply (4)

A1

Which integer comes just before 2?

Need a hint?
  • “Just after” means one step right (+1).
  • Right is the bigger direction.
A2

Which integer comes just after -7?

Need a hint?
  • “Just after” means one step right (+1).
  • Right is the bigger direction.
A3

Which integer comes just before -7?

Need a hint?
  • “Just after” means one step right (+1).
  • Right is the bigger direction.
A4

Which integer comes just before -1?

Need a hint?
  • “Just after” means one step right (+1).
  • Right is the bigger direction.
Extension

Extension (4)

E1

Which integer comes just after 7?

Need a hint?
  • “Just after” means one step right (+1).
  • Right is the bigger direction.
E2

Which integer comes just after 1?

Need a hint?
  • “Just after” means one step right (+1).
  • Right is the bigger direction.
E3

Which integer comes just before -9?

Need a hint?
  • “Just after” means one step right (+1).
  • Right is the bigger direction.
E4

Which integer comes just after 1?

Need a hint?
  • “Just after” means one step right (+1).
  • Right is the bigger direction.