Wednesday
Wednesday: Write expressions
Oliver leaves clue cards along the trail, each one written in careful words.
Bennie finds the first card. It says, "Add 8 and 7, then multiply by 2."
"I can write that with numbers," Bennie says. He writes 2 × 8 + 7.
Oliver tilts his head. "Read your expression again," he says gently.
"Which part do you work out first?" Bennie looks again.
"Oh! I must add 8 and 7 first, so they need parentheses."
He writes 2 × (8 + 7). Oliver hoots happily.
Learn it: words to an expression
Words like "then" tell you the order of the steps.
The step that comes first often goes inside parentheses.
"Add 8 and 7, then multiply by 2" is 2 × (8 + 7). Its value is 30.
2 × 8 + 7 means something else: multiply first, then add 7. Its value is 23.
Some words name a result. A sum is an addition result, and a difference is a subtraction result.
"Multiply 5 by the sum of 6 and 2" is 5 × (6 + 2).
- Read the question.
- Tap your answer.
- Read the question.
- Tap your answer.
- Read the question.
- Tap your answer.
Oliver has 4 bags with 6 acorns in each. He gives away 5 acorns. Which shows how many are left?
Bennie picks 3 apples from each of 5 trees, then 2 more from the ground. Which shows his apples?
Lucy has 18 seeds and finds 6 more. She shares them equally in 4 pots. Which shows each pot?- Read the expression.
- Tap the steps in order.
| Sentence | True or false? |
|---|---|
| "Add 8 and 7, then multiply by 2" is written 2 × (8 + 7). | ? |
| "Multiply 4 by 6, then subtract 5" is written 4 × (6 - 5). | ? |
| "The sum of 6 and 2" means 6 + 2. | ? |
| 2 × (8 + 7) = 30 | ? |
Write the steps as an expression on paper.
Evaluate it.
Then switch: you say the words, and your grown-up writes the expression.
Clever writing! Tomorrow Chris tells a story about very big expressions.