Explain how you can use base ten blocks to find 1.54 +2.37

You could use them to add 154 to 237 (using a flat, 5 longs and 4 units to make 154 and 2 flats, 3 longs and 7 units to get 237). Then once you've put them together, you'll count 391 (you'll have to move the decimal back to 3.91 to get the answer).