Substituting into Formulae

Mathematics · Algebra · ages 11-12

Name ______________________ Date ____________

If x = -3, find the value of x squared, written x^2.
Answer: ______________
If a = 5, b = 3, and c = 4, find the value of a + b × c.
Answer: ______________
If a = 5, what is a + 3?
- 7
- 8
- 15
When you substitute into 2 + 3 x n, you should multiply before you add.
Circle one: True False
If a = 7 and b = 2, find the value of a - (-b)^3.
Answer: ______________
If a = 7 and b = 2, find the value of a - (-b)^2.
Answer: ______________
If x = -2, find the value of x cubed, written x^3.
Answer: ______________
Evaluate 5 + 2 x n when n = 4.
- 13
- 28
- 11
The formula is A = s², where s = -4. What is A?
- -16
- 8
- 16
If a = 2, b = 3, c = 8, d = 2, e = 3, and f = 1, find the value of a × b^2 - c ÷ d^2 × e + f.
Answer: ______________

Answer key

For grown-ups. Fold this page away before handing over the rest.

9 · Squaring a negative number gives a positive answer, because two negative numbers multiply to a positive.
17 · Multiplication comes before addition, so do b × c first, then add a.
8 · Substitute a = 5: 5 + 3 = 8.
True · Multiplication happens before addition, even after substituting a number for n.
15 · Cubing a negative number gives a negative answer, and subtracting a negative adds instead.
3 · Work out the power first, and remember that squaring a negative number gives a positive answer.
-8 · A negative number cubed stays negative, because the third multiplication flips the sign back.
13 · Multiply first: 2 x 4 = 8. Then add: 5 + 8 = 13.
16 · A negative number squared becomes positive: (-4) x (-4) = 16.
13 · Powers come before multiplication and division, and multiplication and division are done left to right before the adding and subtracting.