Vocabulary altogether add total sum total Use the

Vocabulary altogether add total sum total Use the words in the box opposite to define ‘total’.

Can add a two-digit and extend to threedigit number and tens mentally Adding larger numbers together can sometimes appear tricky. With the right method it can be done quickly and sometimes in your head! 54 + 30 = Talk to the person next to you. How could we find the answer?

Can add a two-digit and extend to threedigit number and tens mentally There are two methods that we are going to look at today. Partitioning H Number lines + 10 0 O 354 +10 20 T 100 300 50 4

Can add a two-digit and extend to threedigit number and tens mentally 3 30 is too big a number to count in +1 steps along a number line. How else could we do it? 54 + 30 = ? 54 ? ?

Can add a two-digit and extend to threedigit number and tens mentally Using our knowledge of multiples of 10 we know that 3 x 10 = 30. So, we could do 3 steps of 10 along our number line to get to 30 quickly. +30 +10 54 64 54 + 30 = 84 +10 74 84

Can add a two-digit and extend to threedigit number and tens mentally What about this one? What are the best steps to take? Tell the person next to you. 48 + 30 = +10 48 +10 58 68 78

Your turn Using a number line, complete this calculation using as few steps as possible. 68 + 30 = +10 68 +10 78 88 98

Can add a two-digit and extend to threedigit number and tens mentally Partitioning is more useful when the numbers are even bigger! Show me on your whiteboards how you would partition this number… 354

Can add a two-digit and extend to threedigit number and tens mentally H T O 354 300 50 4 Let’s look at using partitioning to help us with addition calculations…

Can add a two-digit and extend to threedigit number and tens mentally T O 354 + 50= H T O 300 +50 + 4 + 50 + 0 = What this calculation is asking you to do is…

Can add a two-digit and extend to threedigit number and tens mentally 300 + 50 + 4 + 50 + 0 = You might think that this actually looks like there is a lot more to do but in fact this makes it quicker to add up and there is less chance of making a mistake!

Your turn 542 + 40 = Remember to partition the numbers! This will help you to add the numbers up mentally.

Your turn 56 + 40 = 624 + 70 = 419 + 60 =

Your turn There were 735 people taking part in a charity race. At the last minute, another 70 people decided to join in. How many people were at the race altogether?