07052020 LO Adding numbers with different numbers of

07/05/2020 LO: Adding numbers with different numbers of decimal places. Write this in your book. Look out for today’s key words in bold.

Warm up Use mental maths to answer the questions below. See how fast can you do them all. 50 + __ = 70 600 + __ = 615 __ + 300 = 500 380 + ___ = 400 ___ + 900 = 1000 670 + 520 = ____

Warm up 50 + 20 = 70 600 + 15 = 615 200 + 300 = 500 380 + 20 = 400 100 + 900 = 1000 670 + 520 = 1190

Today we’re going to look at adding numbers together with different numbers of decimal places. Let’s look at our first example: 2. 5 + 3. 16 = The first number has ones and tenths but the second number has ones, tenths and hundredths. Let’s look at these numbers on a place value grid using counters. + Now look at the numbers in the column method. Notice how I have lined up the decimal points? Can you find the answer? Don’t worry, we’ll go through it together on the next slide.

First let’s look at the hundredths columns. We have zero hundreds and six hundredths. 0+6=6 + Next we look at the tenths column. 5+1=6 5 6 6 And finally we look at the ones column. 2+3=5 5 6 6

Take a look at this calculation, it has been incorrectly lined up. Have a go at re-writing it in your book.

Did you remember that the decimal points must always be lined up? zero We start with the hundredths column first. Hundredths column 3 3 . 9 7 0+7=7 Tenths column: 8+1=9 Ones column: 2+1=3 Tens column: 3+0=3

What about this one? Write this column addition correctly in your book.

This one was a little more tricky as 534 didn’t have a decimal point. We know that there are 5 hundreds, 3 tens and 4 ones in 534. This means the decimal point must come after the 4. zero 5 3 9. 3 4

Try these additions in your book. 1) 2) 3) Use the column method to work out: 14. 82 + 3. 7 4) 5) Challenge! Gina runs 3. 8 miles on Monday and 3. 29 miles on Tuesday. How many miles does she run in total?

Try these additions in your book. 1) 4) 2) 3) 5) We can add zero here as a placeholder. Challenge! 3 0 78 1 0 2 9 5 1

Well done! I hope you enjoyed learning to add decimals with different numbers of decimal places. Tomorrow we will test our times tables and play some maths games.