Addition and Subtraction

1.

How has the pyramid on the left been completed?
How many ways can you make ten at the top?

2.

How has the second row been calculated?
Which number goes at the top?
Rearrange the numbers 1 to 5 on the bottom row.
What’s the largest top number you can make?

3.

The number three can be written as a sum of whole
numbers in four different ways.
3
2+1
1+2
1+1+1
Investigate for other whole numbers.

4.

What do you notice, what do you wonder?

5.

Three rods are used to make a length of 10.
How many ways can you do it?

6.

Calculate the following:
a) 123 + 456
b) 426 + 153
c) 275 + 304
d) 124 + 456
e) 426 + 163
f) 375 + 304
What do you notice about your answers?

7.

Ten counters are placed randomly into three boxes.
How many ways could they be shared?
What if you had more boxes or counters?

8.

You have one of each coin in your pocket.
You take some out at random.
How many different totals could you make?

9.

Using 2p, 5p and 10p coins, how many ways can you
make a total of 30p?
(5, 2, 1)
How many ways can you make £1?

10.

1)
2)
3)
4)
5)
Choose any 4 digits.
Form the largest four-digit number.
Form the smallest four-digit number.
Subtract the smallest from the largest.
Repeat steps 2 to 4 with the result.
Stop when you think you have a good reason!

11.

1)
2)
3)
4)
5)
6)
Choose 3 different digits.
Form the largest three-digit number.
Form the smallest three-digit number.
Find the difference.
Reverse the digits of your answer.
Add this to the original difference.
What happens if you try it with 4 digits?