Monday
Monday: Parentheses first
Oliver the Owl pushes his glasses up his beak and points to two wooden signs by Puzzle Pond.
The first sign says 2 + 3 × 4. The second sign says (2 + 3) × 4.
"These look almost the same," says Bennie the Bear. "Do they have the same value?"
"An excellent question," says Oliver. "The small curved marks are called parentheses."
"They tell us which part to work out first."
Bennie tries the first sign, and then the second.
His two answers are different! "So the marks really matter," he says.
Learn it: the order to work in
First, work out anything inside parentheses.
Next, multiply and divide, from left to right.
Last, add and subtract, from left to right.
(2 + 3) × 4: the parentheses come first. 2 + 3 = 5, and 5 × 4 = 20.
2 + 3 × 4: multiply first. 3 × 4 = 12, and 2 + 12 = 14.
- Read the question.
- Tap your answer.
- Read the question.
- Tap your answer.
- Read the question.
- Tap your answer.
- Parentheses first, then multiply, then subtract.
- Tap the steps in order.
| Sentence | True or false? |
|---|---|
| (8 + 4) × 3 = 36 | ? |
| 8 + 4 × 3 = 36 | ? |
| (20 - 5) ÷ 5 = 3 | ? |
| 20 - 5 ÷ 5 = 3 | ? |
Then add 2 more spoons on the side. That shows 3 × 4 + 2.
Now make 3 piles with 4 + 2 spoons in each pile. That shows 3 × (4 + 2).
Count both ways. Which way has more spoons?
Well done! Tomorrow Oliver shows groups inside groups.