Look for the second right answer

After a correct answer, ask what else works. Change one thing, then check that the new answer still fits every rule.

One answer is a place to start

12341 × 2 × 3 × 4= 24What else works?
One right answer, and the question to ask next.

A second right answer is a different answer that also fits every rule. Most of us find one answer and stop there.

Finding the second is a habit. After any correct answer, ask "what else works?" before you move on.

More

To look, change one thing: the order, the grouping or the operation. Then check that the new answer still fits every rule. If it does, you have a second right answer.

1Find one answer that fits.

2Ask: what else works?

3Change one thing, then check every rule again.

Lesson help

Two is a habit. Four is a skill. Ask what else works, change one thing, check it still fits.

About this lesson

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One answer is a place to start

A second right answer is a different answer that also fits every rule. Most of us find one answer and stop there.

Finding the second is a habit. After any correct answer, ask "what else works?" before you move on.

To look, change one thing: the order, the grouping or the operation. Then check that the new answer still fits every rule. If it does, you have a second right answer.

1Find one answer that fits.

2Ask: what else works?

3Change one thing, then check every rule again.

12341 × 2 × 3 × 4= 24What else works?
One right answer, and the question to ask next.

Three ways to 24

Make 24 from 1, 2, 3 and 4, using each number once.

First way: 1 × 2 × 3 × 4 = 24.

Change the operation on the first three numbers: 1 + 2 + 3 is 6, and 6 × 4 is 24. That is (1 + 2 + 3) × 4.

Change the grouping: 4 + 2 is 6, 3 + 1 is 4, and 6 × 4 is 24. That is (4 + 2) × (3 + 1).

Same numbers, three right answers. Writing the first way in another order, such as 4 × 3 × 2 × 1, is the same answer, not a new one.

12341 × 2 × 3 × 4= 24(1 + 2 + 3) × 4= 24(4 + 2) × (3 + 1)= 24
Three different answers from the same four numbers.

Find a second way

You have 1, 2, 3 and 4, and one way already: 1 × 2 × 3 × 4. Work out each choice before you pick.

12341 × 2 × 3 × 4= 24(1 + 2 + 3) × 4= ?(1 + 2) × 3 × 4= ?
One way found. Which choice is a second?

Try it

Which is a second right answer?

  1. (1 + 2 + 3) × 4
  2. (1 + 2) × 3 × 4
Show the answer

(1 + 2 + 3) × 4

Right. 1 + 2 + 3 is 6, and 6 × 4 is 24. It uses each number once, so it fits every rule, and it is a different answer from 1 × 2 × 3 × 4.

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