Try Meagan's trick using other numbers. Is there a quick way to find the original number? Explain how it works.

Use Meagan’s trick. Write the steps, in order, to find the original number.

• Subtract 7.
• Add -9.
• Find the opposite.
• Subtract from 12.
• The answer is +10.

Find the original number. State the steps, in order. that you will use.

• Add -31.
• Subtract -9.
• Add 18.
• Subtract from 12.
• The answer is - 12.

Make up a number trick that gives you the original number if you subtract 3 from the result. Your trick must have at least 4 steps.

Make up a number trick that always ends with the original number. Your trick must have at least three steps. One step must involve using an opposite.

Lloyd is lifting weights over a nine week training period. Every week. he lifts 2 kg more than he lifted the previous week. During the ninth week, he lifts 80 kg. How much was he lifting during his first week?

On Monday, Heidi bought some grapes. Each day, she ate half of them. On Friday, only eight grapes were left. How many grapes did Heidi buy?

During a clothing sale, the price goes down by half each day an item is not sold. If an item costs $2.50 after 8 days, what was the original price?

Romona takes a shape and cuts away half of it five times. The following triangle is what remains.

a) Draw the original shape.

b) Draw a polygon that is symmetric. With a single line, divide it into two identical pieces.

Make up a problem you can solve by working backwards. Show how to solve it.

Consider the following diagram. Find a way to move the discs from the first post. as shown, to the third post.

• The discs on the third post must increase in size from top to bottom.
• You cannot place a larger disc on top of a smaller disc.
• You can use all three posts.